Major changes:
- Consolidated schema into single migration with IRC envelope format
- Messages table stores command/from/to/body(JSON)/meta(JSON) per spec
- Per-client delivery queues (client_queues table) with fan-out
- In-memory broker for long-poll notifications (no busy polling)
- GET /messages supports ?after=<queue_id>&timeout=15 long-polling
- All commands (JOIN/PART/NICK/TOPIC/QUIT/PING) broadcast events
- Channels are ephemeral (deleted when last member leaves)
- PRIVMSG to nicks (DMs) fan out to both sender and recipient
- SPA rewritten in vanilla JS (no build step needed):
- Long-poll via recursive fetch (not setInterval)
- IRC envelope parsing with system message display
- /nick, /join, /part, /msg, /quit commands
- Unread indicators on inactive tabs
- DM tabs from user list clicks
- Removed unused models package (was for UUID-based schema)
- Removed conflicting UUID-based db methods
- Increased HTTP write timeout to 60s for long-poll support
Migration 003 created tables with INTEGER keys referencing TEXT primary
keys from migration 002, causing 'no such column' errors. Fix by
properly dropping old tables before recreating with the integer schema.
Rewrite all tests to use the queries.go API (which matches the live
schema) instead of the model-based API (which expected the old UUID
schema).
