[turinglambdaai]

Interaction gap

Taskly's Windows task rows were still SelectionMode="Single", unlike macOS selection behavior and Linux #33. Users couldn't Ctrl/Shift-select a range, keyboard-select multiple tasks, or use Return to edit the focused task.

Changes

• Set task and search-result ListViews to native WinUI Extended selection mode (Ctrl/Shift click, Up/Down, Shift+arrow ranges).
• Enter with exactly one selected task opens its edit dialog; Esc clears the current selection. Preserve native editing keys: TextBox keyboard events are not intercepted.
• Preserve selected task IDs across list and search-result rebuilds, dropping only tasks no longer in the result set. This prevents live backend polls from unpredictably clearing selection.
• Add stable UI Automation IDs and a packaged Windows acceptance assertion that ListView exposes CanSelectMultiple.
• Document remaining parity gaps explicitly.

Dependencies

Stacked on #39 → #36 → #35 → #32. Merge in that order, rebase this PR after dependencies, then run three-platform integrated acceptance.

QA

• Windows x64 native CI and packaged Product Acceptance green
• Click, Ctrl-click, Shift-click, Up/Down and Shift+arrow range selection
• Enter edits a single selected task; Esc clears; search results behave identically
• Selection preserved when tasks are updated/reordered by changed-event refresh
• Quick-add and inline text fields retain Enter/Esc shortcuts
• Checkbox completion, context-menu commands and navigation remain independent of selection

Scope: This PR does not implement batch actions, inline editor or undo. They remain release-blocking parity tasks; do not merge/release based solely on this green check.