refactor(datagrid): direct-draw NSView cell, subview-based overlay editor

[datlechin]

Summary

Fixes the 97% CPU spike during sustained scroll over the data grid. Replaces the NSTableCellView + NSTextField + NSButton + Auto Layout cell with a direct-draw NSView, and replaces the NSPanel-based overlay editor with a subview of the table view so the parent window stays key during edit (toolbar/buttons keep their accent color).

What changed

DataGridCellView: NSTableCellView → NSView direct-draw

• No subviews, no constraints, no NSTextField/NSButton per cell
• draw(_:) paints text via cached NSAttributedString (invalidated only on text/font/color change), then accessory icon (FK arrow or chevron), then optional focus border
• Per-cell-during-scroll cost: zero Auto Layout solving, zero NSCell internal layout, zero NSButton tracking-area work
• Cell text uses NSColor.alternateSelectedControlTextColor (white) when on emphasized selection, falling back to .labelColor otherwise. Matches macOS HIG.
• Accessory SF Symbols use NSImage.SymbolConfiguration(hierarchicalColor:) (correct API for multi-layer symbols like arrow.right.circle.fill); two cached variants per icon (normal + emphasized)
• Right-click walks up to the row view's menu(for:) for context menus
• Accessibility role/label/index range preserved

DataGridRowView: emphasis propagation to cell subviews

• Overrides isSelected and isEmphasized setters to call setNeedsDisplay(true) on every DataGridCellView subview when emphasis changes. NSTableCellView got this for free via interiorBackgroundStyle inheritance from NSCell binding; custom NSView cells need explicit propagation. Without this, only the focused cell would flip text color on row select; sibling cells stayed black.

CellOverlayEditor: NSPanel → subview of the table view

• The editor (NSScrollView containing NSTextView with isFieldEditor = true) is now added as a subview of the table view in the same window
• Window stays key throughout the edit → toolbar/button accent colors don't desaturate
• Outside-click dismiss via NSEvent.addLocalMonitorForEvents
• App-deactivate dismiss via NSApplication.didResignActiveNotification
• Dismiss-on-scroll and dismiss-on-column-resize observers preserved
• Same keyboard policy: Return commits, Option+Return inserts newline, Esc cancels, Tab/Shift+Tab navigates between cells

Editing path consolidation

• tableView(_:shouldEdit:row:) is now a no-op (AppKit doesn't invoke it for custom NSView cells anyway)
• New beginCellEdit(row:tableColumnIndex:) on TableViewCoordinator is the single entry point — called from double-click, single-click-on-focused, Return key, programmatic beginEditing. Routes to editEligibility then showOverlayEditor.
• All edits route through the overlay editor (previously only multi-line did)
• Deleted CellTextField.swift (83 LoC), DataGridFieldEditor, the windowWillReturnFieldEditor branch on TabWindowController, the NSControlTextEditingDelegate / NSTextFieldDelegate conformances on TableViewCoordinator, and the restoreTruncatedDisplay glue

Resize cursor fix

• Stage 9b-revised in refactor(datagrid): drop redundant resize cursor and consolidate sort dispatch #1131 incorrectly assumed NSTableHeaderView auto-handles the resize cursor when column.resizingMask.contains(.userResizingMask). That auto-mechanism doesn't fire for subclassed NSTableHeaderView instances on macOS 14+. Restored the updateTrackingAreas + mouseMoved cursor handling in SortableHeaderView. (Tested: resetCursorRects alone doesn't fire reliably for our subclass; mouseMoved does.)

Diff stats

• 12 files changed, ~424 insertions, ~557 deletions
• 1 file deleted (CellTextField.swift)

Test plan

• Open a 100k+ row table (e.g. seed stress_data from docs/test/sample_postgres_02_data.sql). Sustained scroll (hold arrow, drag scrollbar). CPU should stay reasonable; no 97% spike.
• Click a row. ALL cells in the selected row show white text on accent-blue background. Navigate up/down: text color flips correctly across all cells, not just the focused one.
• FK arrow icon visible against both emphasized and non-emphasized backgrounds (no empty/inverted circles).
• Double-click a plain-text cell → overlay editor appears anchored to the cell. Toolbar buttons (Filters, Apply, Data segment) retain their accent color while editing — no desaturation.
• Edit, press Return → commit. Press Esc → cancel. Tab → next cell. Shift+Tab → previous cell. Cmd+S during edit → commits and triggers menu Save.
• Open a multi-line cell (newlines in value). Overlay shows multi-line content with vertical scroll. Option+Return inserts newline.
• Right-click a cell → row context menu appears.
• Hover column dividers in the header → resize cursor (↔) appears reliably.
• Drag column edge to resize → live resize, cursor consistent.
• Scroll table while overlay editor is open → editor dismisses (commits) on scroll.
• Resize a column while overlay editor is open → editor dismisses (cancels) on column resize.
• Cmd+Tab to another app, come back → overlay dismisses (commits) on app deactivate.
• Modified-column tint, deleted-row strikethrough, focus border on emphasized selection — all preserved.
• VoiceOver: cell announces "Row N, column M: value" with correct role.

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.