[espdesign]

Summary

Resolves #115.

Conforms the /pm calendar ephemeral view (CalendarFeedView) to project UI/UX standards, timeout lifecycle, and session management contracts.

Changes

• Close Button: Added secondary Close button (style=discord.ButtonStyle.secondary, row=0) and callback to CalendarFeedView that cleans up and unregisters from MenuSessionManager.
• Session Management: Registered ephemeral interaction in MenuSessionManager.register_menu(interaction) during /pm calendar. Added MenuSessionManager.update_interaction(...) to maintain active session state across message edits.
• Timeout Token Freshness: Updated CalendarFeedView._on_regenerate_clicked to update self._initial_interaction and synchronize with MenuSessionManager so BaseView.on_timeout operates against a live interaction token rather than an expired one.
• Router Pattern: Delegated view and embed construction in PmCog.calendar to DiscordViewRouter.build_calendar_feed_view(...).
• Specs & Tests: Added unit tests in test_calendar_feed.py, test_hub_menu_dismissal.py, and test_menu_manager.py. Synced requirement changes to openspec/specs/hub-menu-dismissal/spec.md.

Acceptance Criteria

• CalendarFeedView includes a secondary Close button in row 0.
• Clicking Close deletes the ephemeral message and stops the view.
• Ephemeral interaction is registered in MenuSessionManager.register_menu().
• on_timeout() dismisses the message and unregisters the session.
• Unit tests added verifying button layout, close callback, and timeout dismissal.