[vivekjyani]

Context

Multi-select fields (and multi-select table/collection cells) only allowed selecting options one at a time. Spec asks for a bulk Select All / Deselect All control, and the toggle must NOT be one of the selectable options itself.

What changed

• SelectAllToggleButton<T> (new, in MultiSelectionView.swift) — shared, generic toggle rendered above the options box. Selects every option id / clears all; label flips between "Select All" and "Deselect All".
• MultiSelectionView.swift — renders the toggle for the simple form field when multi == true.
• TableMultiSelectView.swift — renders the same toggle, pinned above the sheet's ScrollView, for multi-select table/collection cells; edits go through the existing temp-array → Apply path.
• MultiSelectionDataModel (+ DocumentEditor) — added a mode field (fed from fieldEditMode) so the field view can tell when it's readonly.
• Toggle is hidden in readonly mode on both surfaces (mode != .readonly / cellModel.editMode != .readonly).

Decisions

• One shared generic component (SelectAllToggleButton<T: Identifiable>) instead of two copies — the simple field passes Option, the cell passes OptionLocal; both satisfy getId: (T) -> String?.
• Table/collection toggle writes to the temp array, committed only on Apply, to match the existing cell-sheet behavior (nothing persists until Apply).
• isSelected computed, not @State in TableMultiSelection — a @State copy ignored external array mutations, so Select All didn't update the checkmarks. Computed value stays reactive.
• Readonly hides rather than disables the toggle — a greyed bulk control is noise in a readonly field; options themselves still render.

Screenshot / video

Public API / docs

No public API change — SelectAllToggleButton, MultiSelectionDataModel, and the views are internal; the new mode has a .fill default (non-breaking). No docs update needed.

Test coverage

Covered via XCUITest (UI bridge can't run in CI sandbox; verified on simulator):

• Simple field: Select All, Deselect All, Select-All-then-deselect-one, and editable-only toggle visibility (single-select + readonly excluded).
• Table cell + collection cell: Select All / Deselect All commit on Apply; single-select cell shows no toggle.

Reviewer notes

• No readonly multi: true column exists in the table/collection fixtures, so the readonly-hide path is UI-tested only on the simple field; table/collection share the identical editMode != .readonly gate. Can add a fixture + test if you want explicit coverage.
• The simple-field visibility test asserts exactly 1 toggle — it depends on the fixture having one editable + one readonly multi field; flag if that fixture changes.

[vivekjyani]

Review: approve ✅

Clean approach — one reusable SelectAllToggleButton, reuses the existing onChange / temp-array→Apply paths, hidden in readonly on both surfaces. No public-API or schema impact (new mode is a transient view-model flag, not serialized). Good catch switching TableMultiSelection.isSelected from @State to computed so Select All actually updates the checkmarks.

No blocking issues. Minor nits (non-blocking):

• SelectAllToggleButton<T: Identifiable> — the Identifiable constraint is unused (selection goes through the getId closure); can drop it.
• allOptionsSelected / allTableOptionsSelected are duplicate logic — could be one helper.
• Readonly-hide path for table/collection cells is untested (no readonly multi:true fixture); relies on the shared editMode != .readonly gate. testSelectAllToggleShownOnlyForEditableMultiFields asserting count == 1 is fixture-fragile.

Tests meaningfully assert committed values, not just taps — coverage is adequate for the UI layer. Full analysis in review notes.

[vivekjyani]

Inline review notes (all non-blocking — overall approve). See each thread for detail.