fix(tabs): restore scrolling and pane transfers

[wzz6423]

Summary

• Restore top-level tab hover feedback, compact selected styling, and horizontal tab-strip navigation for trackpads and mouse wheels, including a hover-only scrollbar with a larger grab area.
• Route native-header events through the window frame container so tab clicks, close buttons, scrolling, title-bar controls, resizing, and fullscreen transitions use the intended AppKit views.
• Clear stale close-button hover feedback after tabs are hidden, moved, scrolled, reattached, or the window loses focus.
• Show tab groups as color-only disclosure arrows without names or rename actions, remove the obsolete display-name setting, and reduce the compact control from 34 points to 17 points while preserving its height and centered arrow.
• Add nine Chrome-style color presets to sidebar-group and tab-group color panels only; keep arbitrary color selection and ordinary project/tab color panels unchanged.
• Prevent narrow split panes from expanding into neighboring panes or sidebars while preserving their live terminal surfaces.
• Keep tab grouping in context menus and allow eligible panes or tabs to move across the current header, sidebar projects, and newly created projects without recreating terminal, editor, browser, or split state.
• Fade the full-header drop preview while respecting Reduce Motion, and update the English and Chinese user documentation for the final tab-group behavior.

GitHub Project

• Project: zshell Development

PR Type

• Type: fix

Validation

• Status: passed

• Command: python3 mac/tests/test_workspace_hover.py

• Result: 54 checks passed against the production workspace controls. Coverage includes the 17-point compact group width, bounded row and close-button hover regions, layout and scroll changes, hide/unhide and reattachment, window deactivation, and selected-tab painting.

• Status: passed

• Command: python3 mac/tests/test_workspace_hover.py --source-ref db2631b

• Result: The negative-control run exited 1 as expected with 39 checks passing and 15 failing, including the old 34-point group width and the stale close-button hover cases.

• Status: passed

• Command: python3 mac/tests/test_pane_bounds.py

• Result: 214 checks passed using the production pane chrome, terminal container, and prompt-queue constraints at 32, 80, 160, and 360-point widths. The negative-control run against 5d52516 exited 1 as expected with 118 passing and 96 failing checks.

• Status: passed

• Command: python3 mac/tests/test_tab_strip_scrolling.py

• Result: 50 checks passed in borderless and titled offscreen AppKit fixtures, covering event routing, tab and close-button clicks, bidirectional pixel scrolling, vertical wheel mapping, clamping, thumb dragging before hover callbacks, and overlay cleanup.

• Status: passed

• Command: python3 mac/tests/test_tab_strip_scrolling.py --source-ref 6cde33b

• Result: The negative-control run exited 1 as expected with 20 checks passing and 30 failing, confirming the fixture detects the original routing and scrollbar failures.

• Status: passed

• Command: git diff --check && xcrun swiftc -parse mac/zshell/WorkspaceChromeViews.swift

• Result: Whitespace validation and Swift syntax parsing completed without diagnostics.

• Status: passed

• Command: make update

• Result: The final Debug app built and launched from /Users/wzz/个人/code/zshell with DerivedData at mac/build/debug; the running executable was verified at mac/build/debug/Build/Products/Debug/zshell Debug.app/Contents/MacOS/zshell.

• Status: passed

• Command: codesign --verify --deep --strict --verbose=2 'mac/build/debug/Build/Products/Debug/zshell Debug.app'

• Result: The final Debug bundle is valid on disk and satisfies its designated requirement.

• Status: passed

• Command: Main-worktree Debug app, tab-group and color-panel interaction.

• Result: The 17-point group arrow remained clickable and toggled collapse state without a blue focus ring. No group name was shown. All nine presets fit in one row; red and orange showed the matching outer selection ring with a white inner ring, and choosing orange updated the tab-group marker to #FA903E immediately.

• Status: passed

• Command: Main-worktree Debug app, pointer-driven four-pane divider resize and tab switching.

• Result: The divider was dragged in both directions and restored. Terminal content and pane borders followed without overlapping adjacent panes or sidebars, and moving the pointer away left no unrelated tab or close-button hover backgrounds.

• Status: passed

• Command: jq empty mac/zshell/Localizable.xcstrings && (cd web && bun run typecheck && bun run build)

• Result: The String Catalog is valid JSON, website type checking passed, and the production build prerendered all 38 routes successfully.

• Status: not run

• Reason: Physical trackpad gestures, full-header pane-drop animation, and terminal-backend-specific transfer paths still require manual acceptance. They are separate from the group-control, divider, hover, and color-panel paths verified above.

Risk and Rollback

• Risk: The native header now shares the window frame container with the hosting view. The compact group target is intentionally half its previous width, and the shared color panel installs an accessory only for group colors. Resizing, fullscreen transitions, physical trackpad feel, and cross-backend transfers still need broader acceptance.
• Rollback: Revert this pull request.

Related Issue

None

AI Attribution

• Agent: Codex
• Co-authored-by: Codex noreply@openai.com

[github-actions]

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• There is no unit test target: app changes are proven by building and running Zshell and exercising the change, so say in Validation what you did and attach screenshots or a recording for UI work. Run cargo test --locked in mac/Vendor/alacritty-bridge for bridge changes, bun run typecheck && bun run build in web/ for site changes, and bunx tsc --noEmit in mac/ for anything under mac/scripts/. Install dependencies with bun install --frozen-lockfile in each package before running Bun checks.

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