[Admin Console] Phase 5: Event Search and Inspection #635

Inspecting stored relay events requires writing raw SQL queries against the PostgreSQL database. Operators have no way to search events from a browser.

• GET /admin/events with query params: event id, author pubkey, kind, tag filters, created-at range, result limit
• Results returned as JSON
• Integrate NIP-50 full-text search once the SoB NIP-50 PR lands