fix: Fix memory system persistence and consolidate language prefs

- Replace separate bot-crypto/bot-memories volumes with single bot-data:/data
  volume so user_keys.json and language_prefs.json persist across restarts
- Remove redundant language_prefs.json infrastructure (constant, load/save,
  dict) — language preference now read from memories (last match wins)
- Add robust JSON extraction in _extract_memories (regex fallback for
  markdown fences, embedded arrays, non-array responses)
- Add info-level logging throughout memory extraction pipeline
- Add asyncio.wait_for timeout (15s) on memory extraction to prevent hangs
- Add !ai memory <fact> command for explicit, reliable memory storage
- Update _get_preferred_language to return last match (most recent wins)
- Update !ai forget to clear in-memory caches (pending translate/reply)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -18,9 +18,7 @@ services:
       - WILDFILES_BASE_URL
       - WILDFILES_ORG
     volumes:
-      - bot-crypto:/data/crypto_store
-      - bot-memories:/data/memories
+      - bot-data:/data
 
 volumes:
-  bot-crypto:
-  bot-memories:
+  bot-data: