Calendar entries never render the primary field as an editable cell, unlike Board

[brylie]

Problem

Board renders a record's primary field (#96) as a fully live-editable cell (PropertyValueCell) in the card's title slot. Calendar, by contrast, always renders its entries' titles as static text via entryTitle(row) — never editable inline, regardless of which field is the primary field. This predates #96 (Calendar never made any field's title editable), but #96 makes the asymmetry more visible now that "primary field" is a named, user-facing concept applied identically across both views everywhere else.

Scope

• Decide whether Calendar's scheduled/unscheduled entry titles should render the primary field via PropertyValueCell (matching Board), or whether static text is intentional for Calendar's denser entry rows — this is a UX call, not just an implementation detail.
• If made editable: update CalendarCollectionView.svelte's scheduled-entry and unscheduled-entry markup (src/lib/components/CalendarCollectionView.svelte) to render the primary field the same way Board does, keeping entryTitle/primaryFieldDisplayValue as the fallback for when no primary field resolves.
• If left as static text: document the asymmetry as intentional in collection-views.md §4/§7 rather than leaving it as an unexplained difference.
• Add/update a Calendar component test covering whichever behavior is chosen.

Non-goals

• Not changing Board's existing editable-title behavior.

Done when

Calendar's entry-title editability (or lack of it) relative to Board is a deliberate, documented, tested choice.

[brylie]

Set Priority: P2.

Pre-existing asymmetry (Calendar has never made entry titles inline-editable) made more visible by #96, not introduced by it. Needs a UX call, not urgent.