Create event form

[exyw]

Summary
This PR introduces the full Create Event flow for club profiles and wires it end‑to‑end with Supabase + the OpenAI events vector store. It also adds the Events card to club pages and enables owners to edit events directly.

Major changes

• Create Event form built and styled to match the mock (poster preview, color theme, sections).
• Add Event bottom sheet + edit mode (prefilled Create Event form).
• Club Events card added to club profiles (draggable chunk), showing upcoming events.
• Owner‑only expand/collapse list and edit flow.
• Supabase persistence for events + location + pricing.
• Vector store upload on create + sync on edit; delete endpoints included.
• Thumbnail uploads to Supabase Storage (bucket: auto_instagram_cache).

Notes / TODO

• Storage upload requires bucket policy (see TODO in storage.ts).
• Event tags still placeholders (not persisted yet).

Testing

• Create event and verify it appears in Events card.
• Edit event and confirm data updates + vector store sync.
• Thumbnail upload succeeds.
• Owner “show all / show less” works; non‑owners still see modal view.