Broaden app volume mount from /data/images to /data

Single named volume app_data covering the entire /data directory so
future persistent storage (uploads, exports, etc.) doesn't need
additional volume entries.

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

docker-compose.yml

@@ -9,9 +9,9 @@ services:
       ollama:
         condition: service_started
     volumes:
-      - image_cache:/data/images
-      # To use a bind mount instead (gives direct host access to cached images):
-      # - ./image_cache:/data/images
+      - app_data:/data
+      # To use a bind mount instead (gives direct host access to all app data):
+      # - ./data:/data
     environment:
       DATABASE_URL: "postgresql+asyncpg://${POSTGRES_USER:-fabled}:${POSTGRES_PASSWORD:-fabled}@db:5432/${POSTGRES_DB:-fabledassistant}"
       OLLAMA_URL: "http://ollama:11434"
@@ -62,4 +62,4 @@ services:
 volumes:
   pgdata:
   ollama_models:
-  image_cache:
+  app_data: