Phase 3: Unified Cheshire Cat integration with WebSocket-based per-user isolation

Key changes:
- CatAdapter (bot/utils/cat_client.py): WebSocket /ws/{user_id} for chat
  queries instead of HTTP POST (fixes per-user memory isolation when no
  API keys are configured — HTTP defaults all users to user_id='user')
- Memory management API: 8 endpoints for status, stats, facts, episodic
  memories, consolidation trigger, multi-step delete with confirmation
- Web UI: Memory tab (tab9) with collection stats, fact/episodic browser,
  manual consolidation trigger, and 3-step delete flow requiring exact
  confirmation string
- Bot integration: Cat-first response path with query_llama fallback for
  both text and embed responses, server mood detection
- Discord bridge plugin: fixed .pop() to .get() (UserMessage is a Pydantic
  BaseModelDict, not a raw dict), metadata extraction via extra attributes
- Unified docker-compose: Cat + Qdrant services merged into main compose,
  bot depends_on Cat healthcheck
- All plugins (discord_bridge, memory_consolidation, miku_personality)
  consolidated into cat-plugins/ for volume mount
- query_llama deprecated but functional for compatibility

cat-plugins/discord_bridge/plugin.json

@@ -0,0 +1,10 @@
+{
+  "name": "Discord Bridge",
+  "description": "Discord integration with unified user identity and sleep consolidation support",
+  "author_name": "Miku Bot Team",
+  "author_url": "",
+  "plugin_url": "",
+  "tags": "discord, memory, consolidation",
+  "thumb": "",
+  "version": "1.0.0"
+}