feat: canvas directory - rename, thumbnail preview with auto-save, search/sort, save indicator

[calebyhan]

Description

Account dashboard revamp.

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔨 Refactoring (no functional changes)
• ✅ Test additions or updates
• 🔧 Configuration/build changes

Related Issues

Closes #24

Changes Made

• Added canvas preview
• Added saving indicator on canvas
• Added search/filter canvas on dashboard

Checklist

• My code follows the project's style guidelines (PEP 8 for Python, ESLint for TypeScript)
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Additional Context

N/A

---

[Copilot]

Pull request overview

This PR revamps the canvas “directory” experience by adding persisted canvas thumbnails, rename support, search/sort on the dashboard, and an in-canvas save indicator—backed by a new thumbnail field on canvases in the backend API/schema.

Changes:

• Add thumbnail (JSON) support end-to-end: DB schema, backend list/get/update APIs, and frontend API types.
• Add dashboard UX features: thumbnail preview cards, rename modal for owned canvases, and search/sort controls for owned/shared lists.
• Add debounced thumbnail auto-save from the canvas editor and display a save-state indicator in the top navigation.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail type and allows PATCH updates to include thumbnails.
frontend/hooks/useCanvas.ts	Adds renameCanvas() and wires it into owned-canvas flows.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a save-state indicator UI.
frontend/components/dashboard/SharedCanvases.tsx	Adds search + sort UI and filtered rendering for shared canvases.
frontend/components/dashboard/MyCanvases.tsx	Adds search + sort UI and passes rename handler into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Implements thumbnail preview rendering and an owned-canvas rename modal entrypoint.
frontend/components/AutoVizAgent.tsx	Adds debounced thumbnail auto-save and propagates save state to TopNavigation.
backend/database/schema.sql	Adds thumbnail JSONB column to canvases schema.
backend/app/api/routes/canvases.py	Returns thumbnail in list/get/shared responses and accepts it in PATCH updates.

Comments suppressed due to low confidence (2)

backend/app/api/routes/canvases.py:312

• updates = body.model_dump(exclude_unset=True) will include fields explicitly set to null (e.g. { "name": null }), which will attempt to write NULL into a NOT NULL column and likely bubble up as a 500 from Supabase/PostgREST. Consider validating updates before calling .update() (e.g., reject name is None / blank, and possibly sanitize thumbnail), and return a 4xx error instead of relying on the DB constraint failure path.

    updates = body.model_dump(exclude_unset=True)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )
    return result.data[0]

backend/app/api/routes/canvases.py:312

• New persisted behavior is being introduced (thumbnail JSON stored on canvases and returned from list/get/shared, plus new PATCH field), but backend tests don’t currently cover it. Please add tests that (1) PATCHing a valid thumbnail stores/returns it, (2) invalid thumbnail shapes are rejected, and (3) list/shared responses include the thumbnail field when present.

@router.patch("/{canvas_id}", response_model=Dict[str, Any])
async def update_canvas(canvas_id: str, body: UpdateCanvasRequest, user_id: str = Depends(require_user)):
    supabase = get_supabase_client()
    permission = await get_canvas_permission(canvas_id, user_id, supabase)
    if permission not in ("owner", "edit"):
        raise HTTPException(status_code=403, detail="Edit access required")

    updates = body.model_dump(exclude_unset=True)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )
    return result.data[0]

[Copilot]

Pull request overview

Implements the canvas directory/dashboard revamp by adding thumbnail previews, rename support, search/sort on the dashboard, and an auto-save indicator tied to thumbnail persistence.

Changes:

• Add thumbnail support across backend schema + canvases API responses, and expose it in frontend API types.
• Add thumbnail rendering to owned/shared canvas cards and auto-save thumbnail updates from the canvas editor.
• Add dashboard search + sort, plus owned-canvas rename UX and hook support.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail + thumbnail fields; extends PATCH payload shape.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper and wires it into owned canvases state updates.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a dynamic save indicator.
frontend/components/dashboard/SharedCanvases.tsx	Adds search + sort UI and filtering for shared canvases list.
frontend/components/dashboard/MyCanvases.tsx	Adds search + sort and wires rename into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail preview rendering and rename modal/menu action in cards.
frontend/components/AutoVizAgent.tsx	Implements debounced thumbnail auto-save and forwards save state to top nav.
backend/database/schema.sql	Adds thumbnail JSONB column to canvases.
backend/app/api/routes/canvases.py	Plumbs thumbnail through list/get/shared and PATCH request model.

[Copilot]

Pull request overview

Updates the account dashboard “canvas directory” experience by adding canvas thumbnails (with auto-save), rename support, search/sort, and a more informative save indicator, with backend support for persisting thumbnail JSON.

Changes:

• Added thumbnail to canvas models and endpoints; added DB column (thumbnail JSONB).
• Implemented thumbnail preview cards + rename modal; added search and sort to owned/shared canvas lists.
• Added debounced thumbnail auto-save in the canvas editor and surfaced save state in the top navigation.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail and extends canvas update/type definitions to include thumbnail.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper wiring to the canvas update endpoint.
frontend/components/navigation/TopNavigation.tsx	Replaces “Auto-saved” badge with a SaveIndicator showing saving/saved states.
frontend/components/dashboard/SharedCanvases.tsx	Adds search + sort UI and filtered rendering for shared canvases.
frontend/components/dashboard/MyCanvases.tsx	Adds search + sort + rename wiring for owned canvases.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail preview rendering and a rename dialog/menu action on canvas cards.
frontend/components/AutoVizAgent.tsx	Adds debounced thumbnail auto-save and passes save state to the top nav.
backend/database/schema.sql	Adds thumbnail JSONB column to canvases table (plus commented migration hint).
backend/app/api/routes/canvases.py	Adds thumbnail to list/get responses and allows thumbnail updates via PATCH.

Comments suppressed due to low confidence (1)

backend/app/api/routes/canvases.py:312

• This PR adds new behavior (persisting thumbnail via PATCH and returning it from list/get), but the existing route tests don’t cover setting a thumbnail or clearing it back to null. Adding focused tests around PATCH thumbnail update/clear would help prevent regressions, especially given the changed update serialization behavior.

@router.patch("/{canvas_id}", response_model=Dict[str, Any])
async def update_canvas(canvas_id: str, body: UpdateCanvasRequest, user_id: str = Depends(require_user)):
    supabase = get_supabase_client()
    permission = await get_canvas_permission(canvas_id, user_id, supabase)
    if permission not in ("owner", "edit"):
        raise HTTPException(status_code=403, detail="Edit access required")

    updates = body.model_dump(exclude_unset=True)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )
    return result.data[0]

[Copilot]

Pull request overview

Adds “canvas directory” enhancements to the dashboard/canvas UX, including thumbnail previews persisted to the backend, rename support, search/sort controls, and an in-canvas save status indicator.

Changes:

• Add thumbnail (JSONB) to canvases and expose it via canvas list/detail/shared APIs + update endpoint.
• Generate and auto-save lightweight thumbnail metadata from canvas layout changes; display save state in top navigation.
• Enhance dashboard canvas cards with SVG thumbnail preview, rename action, and search/sort UI for owned/shared canvases.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail type and includes thumbnail in canvas types + update payload.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper that PATCHes canvas name and updates local state.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with dynamic save indicator UI.
frontend/components/dashboard/SharedCanvases.tsx	Adds search and sort UI + filtered rendering for shared canvases.
frontend/components/dashboard/MyCanvases.tsx	Adds search/sort and wires rename action into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail SVG preview rendering + rename modal + layout tweaks.
frontend/components/AutoVizAgent.tsx	Debounced auto-save of thumbnail metadata on layout changes; passes save state to top nav.
backend/database/schema.sql	Adds thumbnail JSONB column to canvases table (with commented “migration” line).
backend/app/api/routes/canvases.py	Adds thumbnail to selects/responses and supports updating/clearing thumbnail via PATCH.

[Copilot]

Pull request overview

This PR revamps the canvas “directory” experience on the account dashboard by adding canvas thumbnails, rename, search/sort controls, and an auto-save status indicator, backed by a new thumbnail field persisted on canvases in the backend.

Changes:

• Add a thumbnail JSON field to canvases (DB + API) and extend the frontend Canvas types to include it.
• Add dashboard UX improvements: thumbnail previews, rename flow, search + sort for owned/shared canvases.
• Add an auto-save indicator in the top navigation driven by debounced thumbnail updates from the canvas page.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail typing and allows updating thumbnail via PATCH.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper to update canvas name and refresh local state.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a stateful save indicator.
frontend/components/dashboard/SharedCanvases.tsx	Adds search + sort UI and filtering for shared canvases.
frontend/components/dashboard/MyCanvases.tsx	Adds search + sort UI, filtering, and rename wiring for owned canvases.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail preview rendering and a rename modal/action in the canvas card menu.
frontend/components/AutoVizAgent.tsx	Implements debounced thumbnail auto-save and surfaces save state to TopNavigation.
backend/database/schema.sql	Adds thumbnail JSONB column to the canvases table definition.
backend/app/api/routes/canvases.py	Adds thumbnail to list/get/selects and supports updating/clearing it via PATCH.

[Copilot]

Pull request overview

This PR extends the canvas “directory” experience (dashboard) by adding thumbnail previews with auto-save, canvas rename, search/sort controls, and an in-canvas save indicator, backed by a new thumbnail field on canvases in the backend.

Changes:

• Add thumbnail JSON payload support to canvases (DB schema, API responses, PATCH updates, frontend types).
• Implement debounced thumbnail auto-save from the canvas editor and display a save state indicator in the top nav.
• Upgrade dashboard canvas lists/cards with thumbnail previews, search/sort, and rename UI for owned canvases.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail type + thumbnail field to canvas models and update payload.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper that PATCHes canvas name and updates local state.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a save-state indicator.
frontend/components/dashboard/SharedCanvases.tsx	Adds query + sort UI and applies filtering/sorting to shared canvases list.
frontend/components/dashboard/MyCanvases.tsx	Adds query + sort UI and wires rename action into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Renders thumbnail previews, adds rename modal + action menu updates.
frontend/components/AutoVizAgent.tsx	Debounced thumbnail auto-save based on layout changes; forwards save status to top nav.
backend/database/schema.sql	Adds thumbnail JSONB column to canvases schema (with a commented migration hint).
backend/app/api/routes/canvases.py	Adds thumbnail to list/get/shared selects and allows PATCH updates for thumbnail.

Comments suppressed due to low confidence (1)

backend/app/api/routes/canvases.py:317

• The new thumbnail behavior (setting/clearing thumbnail via PATCH, and returning thumbnail from list/get/shared responses) isn’t covered by the existing canvas route tests. Adding tests for updating a thumbnail, clearing it with null, and verifying it appears in list/get responses would help prevent regressions.

@router.patch("/{canvas_id}", response_model=Dict[str, Any])
async def update_canvas(canvas_id: str, body: UpdateCanvasRequest, user_id: str = Depends(require_user)):
    supabase = get_supabase_client()
    permission = await get_canvas_permission(canvas_id, user_id, supabase)
    if permission not in ("owner", "edit"):
        raise HTTPException(status_code=403, detail="Edit access required")

    updates = body.model_dump(exclude_unset=True)
    # Drop None for name (NOT NULL) and description (nullable but not clearable via this endpoint);
    # allow thumbnail=None to pass through so clients can explicitly clear the thumbnail
    for field in ("name", "description"):
        if updates.get(field) is None:
            updates.pop(field, None)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )
    return result.data[0]

[Copilot]

Pull request overview

Adds “canvas directory” enhancements across backend + frontend to support dashboard browsing improvements and in-canvas auto-saving UX, including persisted thumbnail previews.

Changes:

• Persist and return a thumbnail JSONB field for canvases (schema + API + frontend types).
• Add debounced auto-save of canvas thumbnails and a “saving/saved” indicator in the top navigation.
• Add dashboard search/sort plus owned-canvas rename UI and thumbnail previews in canvas cards.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail type and supports updating thumbnail via canvasAPI.update.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper and wires it into owned canvases state updates.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a save-state indicator component.
frontend/components/dashboard/SharedCanvases.tsx	Adds client-side search + sort controls for shared canvases listing.
frontend/components/dashboard/MyCanvases.tsx	Adds client-side search + sort and wires rename handler into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail preview rendering and an owned-canvas rename dialog/actions menu.
frontend/components/AutoVizAgent.tsx	Implements debounced thumbnail auto-save and passes save-state into navigation.
backend/database/schema.sql	Adds thumbnail column to canvases (plus idempotent ALTER for existing DBs).
backend/app/api/routes/canvases.py	Exposes thumbnail in list/get/shared and allows PATCH updates for it.

Comments suppressed due to low confidence (1)

backend/app/api/routes/canvases.py:316

• New thumbnail behavior (persisting thumbnail via PATCH and returning it from list/get/shared) isn’t covered by the existing canvases route tests. Since this changes API behavior and is used for the dashboard preview, add pytest coverage for: setting a thumbnail, clearing it with null, and verifying list/get/shared include the field.

@router.patch("/{canvas_id}", response_model=Dict[str, Any])
async def update_canvas(canvas_id: str, body: UpdateCanvasRequest, user_id: str = Depends(require_user)):
    supabase = get_supabase_client()
    permission = await get_canvas_permission(canvas_id, user_id, supabase)
    if permission not in ("owner", "edit"):
        raise HTTPException(status_code=403, detail="Edit access required")

    updates = body.model_dump(exclude_unset=True)
    # Drop None for name (NOT NULL) and description (nullable but not clearable via this endpoint);
    # allow thumbnail=None to pass through so clients can explicitly clear the thumbnail
    for field in ("name", "description"):
        if updates.get(field) is None:
            updates.pop(field, None)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )

[Copilot]

Pull request overview

Adds “canvas directory” enhancements across the frontend dashboard and backend canvases API to support thumbnails, renaming, search/sort, and an autosave indicator.

Changes:

• Add thumbnail payload support to canvases API + DB schema, and render thumbnail previews in dashboard cards.
• Add canvas rename flow for owned canvases and add search/sort UI for owned/shared canvases.
• Debounced auto-save of thumbnail snapshots from the canvas editor, with a save-state indicator in the top navigation.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail type and wires thumbnail into canvas types + PATCH update payload.
frontend/hooks/useCanvas.ts	Adds renameCanvas() hook method and updates local canvas list state.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a live save indicator (saving/saved + relative time).
frontend/components/dashboard/SharedCanvases.tsx	Adds search + sort controls and applies filtering/sorting to shared canvases list.
frontend/components/dashboard/MyCanvases.tsx	Adds search + sort controls and passes rename handler into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail preview rendering and a rename dialog + actions menu entry.
frontend/components/AutoVizAgent.tsx	Implements debounced thumbnail auto-save on layout change and passes save state to navigation.
backend/database/schema.sql	Adds thumbnail JSONB column to canvases.
backend/app/api/routes/canvases.py	Adds thumbnail support to list/get/shared responses and PATCH update request handling.

Comments suppressed due to low confidence (1)

backend/app/api/routes/canvases.py:317

• The new thumbnail update behavior (including allowing thumbnail=null to clear it and ensuring the value is returned in list/get responses) isn’t covered by the existing canvas route tests. Please add/extend tests to assert thumbnail round-trips and that clearing works, so this feature doesn’t regress.

@router.patch("/{canvas_id}", response_model=Dict[str, Any])
async def update_canvas(canvas_id: str, body: UpdateCanvasRequest, user_id: str = Depends(require_user)):
    supabase = get_supabase_client()
    permission = await get_canvas_permission(canvas_id, user_id, supabase)
    if permission not in ("owner", "edit"):
        raise HTTPException(status_code=403, detail="Edit access required")

    updates = body.model_dump(exclude_unset=True)
    # Drop None for name (NOT NULL) and description (nullable but not clearable via this endpoint);
    # allow thumbnail=None to pass through so clients can explicitly clear the thumbnail
    for field in ("name", "description"):
        if updates.get(field) is None:
            updates.pop(field, None)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )
    return result.data[0]

[Copilot]

Pull request overview

Adds canvas thumbnail support end-to-end (DB → API → client) and enhances the dashboard/canvas UX with previews, search/sort, rename, and a save indicator.

Changes:

• Persist canvases.thumbnail (JSONB) in the backend and expose it via canvas list/get/shared APIs and PATCH updates.
• Auto-generate and debounce-save thumbnails from the canvas layout, and surface a save-state indicator in the top navigation.
• Update dashboard cards to show thumbnail previews, plus add search/sort controls and an owned-canvas rename action.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail types and extends canvas update payload to include thumbnail.
frontend/hooks/useCanvas.ts	Adds renameCanvas helper that PATCHes canvas name and updates local state.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a save-state indicator (saving/saved).
frontend/components/dashboard/SharedCanvases.tsx	Adds client-side search + sorting for shared canvases.
frontend/components/dashboard/MyCanvases.tsx	Adds client-side search + sorting and wires rename callback into owned cards.
frontend/components/dashboard/CanvasCard.tsx	Renders thumbnail previews, adds owned-canvas actions menu + rename modal, and updates card layout.
frontend/components/AutoVizAgent.tsx	Implements debounced thumbnail auto-save based on layout key and plumbs save-state to top nav.
backend/database/schema.sql	Adds thumbnail JSONB column to the canvases table (plus an ALTER for existing DBs).
backend/app/api/routes/canvases.py	Accepts thumbnail in PATCH updates and includes it in canvas list/get/shared responses.

[Copilot]

Pull request overview

Implements an upgraded canvas “directory” experience in the dashboard (owned + shared canvases) with search/sort, renaming, and thumbnail previews that auto-save from the canvas editor, plus a live save indicator in the top navigation.

Changes:

• Added thumbnail support across DB schema, backend canvas routes, and frontend API types.
• Implemented debounced auto-save of canvas thumbnails from the editor and surfaced save status in TopNavigation.
• Enhanced dashboard canvas lists with search + sorting and added a rename flow from canvas cards.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
frontend/lib/api/backendClient.ts	Adds CanvasThumbnail types and updates PATCH typing to Partial<Canvas> including thumbnail.
frontend/hooks/useCanvas.ts	Adds renameCanvas and merges partial PATCH responses into local state.
frontend/components/navigation/TopNavigation.tsx	Replaces static “Auto-saved” badge with a SaveIndicator showing saving/saved state.
frontend/components/dashboard/SharedCanvases.tsx	Adds search input + sort selector and uses filtered/sorted list.
frontend/components/dashboard/MyCanvases.tsx	Adds search + sort; wires rename callback into owned canvas cards.
frontend/components/dashboard/CanvasCard.tsx	Adds thumbnail preview rendering and a rename dialog + improved actions menu.
frontend/components/AutoVizAgent.tsx	Adds debounced thumbnail auto-save to backend and passes save state to top nav.
backend/database/schema.sql	Adds thumbnail JSONB to canvases (plus an ALTER TABLE ... IF NOT EXISTS migration line).
backend/app/api/routes/canvases.py	Adds thumbnail to list/get responses and supports updating it via PATCH.

Comments suppressed due to low confidence (1)

backend/app/api/routes/canvases.py:317

• The new thumbnail update behavior isn’t covered by the existing canvases route tests. Adding tests for PATCHing thumbnail (set + clear with null) and verifying it’s returned by GET/list endpoints would help prevent regressions in the autosave/preview feature.

@router.patch("/{canvas_id}", response_model=Dict[str, Any])
async def update_canvas(canvas_id: str, body: UpdateCanvasRequest, user_id: str = Depends(require_user)):
    supabase = get_supabase_client()
    permission = await get_canvas_permission(canvas_id, user_id, supabase)
    if permission not in ("owner", "edit"):
        raise HTTPException(status_code=403, detail="Edit access required")

    updates = body.model_dump(exclude_unset=True)
    # Drop None for name (NOT NULL) and description (nullable but not clearable via this endpoint);
    # allow thumbnail=None to pass through so clients can explicitly clear the thumbnail
    for field in ("name", "description"):
        if updates.get(field) is None:
            updates.pop(field, None)
    if not updates:
        raise HTTPException(status_code=400, detail="No fields to update")

    result = await asyncio.to_thread(
        lambda: supabase.table("canvases").update(updates).eq("id", canvas_id).execute()
    )
    return result.data[0]