See inherited scope from other phases on work area cards

Phases now show inherited scope items that surface as context, no more confusing empty work area cards.

What's New

Work area cards now distinguish between scope items this phase owns and items inherited from sibling phases. When a phase owns no scope but inherits from others, the card displays "N items from other phases" instead of an empty "0 scope items" state. This makes it immediately clear whether a phase has its own scope work or is operating in context-only mode.

Scope-sheet editing is also more responsive now. Changes to assessments, notes, and checklists no longer trigger a page refresh on every keystroke — the page syncs once when you close the sheet, and only if you actually made edits. A small quality-of-life fix: the "Add Work Areas" picker no longer reopens behind the create form once a new work area is added.