fix(web): handle calendar event editor bugs

[Uarmagan]

Summary

• Prevent new recurring event creation from opening the recurrence update-scope dialog before the event exists.
• Skip the update-scope dialog for recurring instances that only have one occurrence, since there is no meaningful choice to make.
• Keep Day calendar event keyboard activation on the event card so Enter/Space does not continue into broader shortcut handling.
• Keep the Week timed-event editor open when its action menu is open, including when moving through Duplicate/Delete.
• Keep shared modal panels above floating event editors and menus, so the recurring delete scope dialog is not covered by the editor.
• Add regression coverage for the recurring submit paths, keyboard behavior, and nested event action-menu focus behavior.
• Investigated the Week "Move To Sidebar" menu item: it is wired to an existing calendar-to-Someday conversion path and saves through the existing event saga, so this PR leaves that behavior in place for now.

Root cause

A new recurring draft was being treated like an existing recurring event because the confirmation gate only checked for a recurrence rule, not whether the event already existed.

A saved recurring instance can still have recurrence metadata even when the series only contains one occurrence. The old gate showed the update-scope dialog for that event even though applying the change directly is the only useful outcome.

Day event cards opened from the keyboard, but the same activation key kept bubbling upward. That left parent/global shortcut handling free to react to the same key press after the form opened.

The Week editor action menu was allowed to move focus into menu items in a way the surrounding editor treated as leaving the edit surface. That made the editor close while moving over menu options.

The shared modal backdrop was on the same base layer as calendar maximum z-index, while floating event editors sit one layer above it. That let the editor paint over the recurring delete scope dialog.

Closes #1837
Closes #1838

Validation

• cd packages/web && bun test src/views/Forms/ActionsMenu/ActionsMenu.test.tsx src/views/Week/components/Draft/grid/GridDraft.test.tsx
• bun lint
• bun type-check
• git diff --check
• Browser check on http://localhost:9080/week: opened a Week draft action menu and confirmed the editor/menu stayed open while moving focus through the menu surface.
• Browser check on http://localhost:9080/day/2026-05-31: i then Enter opened the event form without crashing.
• Browser check on http://localhost:9080/day/2026-05-31: m opened the event form without crashing.
• Browser check on http://localhost:9080/day/2026-05-31: command palette "Edit event" opened the event form without crashing.

Manual note

The local temporary account disables Repeat, so the exact Week recurring-create browser flow could not be completed locally. The recurrence save decision, including the single-occurrence follow-up, is covered by focused regression tests.

For the final modal layer follow-up, the in-app browser automation endpoint did not expose the open tab, so the modal-over-editor behavior was not re-clicked in-browser after the code change.