feat: migrate app_config volume to storage-service config bucket (Phase 3)

All JSON config files (AI settings, doc settings, appearance, themes) now live
in the 'config' bucket of storage-service instead of a shared Docker volume.

- backend/core/config_storage.py: new async HTTP helpers for config bucket r/w
- backend/core/app_config.py: fully async rewrite; all load_*/save_*/seed_*
  functions use config_storage instead of filesystem
- backend/routers/settings.py: all asyncio.to_thread() wrappers removed; direct
  await calls throughout; update_theme reads via load_theme_by_id()
- backend/main.py: await seed_builtin_themes() directly (no to_thread)
- ai-service: remove CONFIG_PATH, add STORAGE_SERVICE_URL; config_reader now
  fetches from storage-service via httpx
- doc-service: config_reader rewritten to fetch/write via storage-service
- docker-compose: remove app_config volume; add storage-service depends_on for
  ai-service; remove DATA_DIR and CONFIG_PATH from doc-service

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

features/ai-service/app/core/config.py

@@ -3,7 +3,7 @@ from pydantic_settings import BaseSettings
 
 class Settings(BaseSettings):
     PROJECT_NAME: str = "ai-service"
-    CONFIG_PATH: str = "/config/ai_service_config.json"
+    STORAGE_SERVICE_URL: str = "http://storage-service:8020"
 
     model_config = {"env_file": ".env", "extra": "ignore"}
 

features/ai-service/app/services/config_reader.py

@@ -1,5 +1,5 @@
 """
-Reads ai_service_config.json from the shared config volume.
+Reads ai_service_config.json from the storage-service config bucket.
 30-second TTL cache + env var overrides (dev credentials stay out of git).
 
 Env var overrides (all optional):
@@ -8,15 +8,17 @@ Env var overrides (all optional):
   OLLAMA_BASE_URL, OLLAMA_MODEL, OLLAMA_API_KEY
   ANTHROPIC_API_KEY, ANTHROPIC_MODEL
 """
-import asyncio
 import json
 import os
 import time
 from copy import deepcopy
-from pathlib import Path
+
+import httpx
 
 from app.core.config import settings
 
+_CONFIG_KEY = "ai_service_config.json"
+
 _DEFAULT_CONFIG: dict = {
     "provider": "lmstudio",
     "timeout_seconds": 60,
@@ -31,12 +33,18 @@ _cache_at: float = 0.0
 _CACHE_TTL = 30.0
 
 
-def _read_config_sync() -> dict:
-    path = Path(settings.CONFIG_PATH)
-    if not path.exists():
-        return _apply_env_overrides(deepcopy(_DEFAULT_CONFIG))
-    with open(path) as f:
-        return _apply_env_overrides(json.load(f))
+def _storage_url() -> str:
+    return f"{settings.STORAGE_SERVICE_URL}/objects/config/{_CONFIG_KEY}"
+
+
+async def _fetch_config() -> dict:
+    """Fetch config from storage-service. Returns defaults if not found."""
+    async with httpx.AsyncClient(timeout=10.0) as client:
+        resp = await client.get(_storage_url())
+        if resp.status_code == 404:
+            return deepcopy(_DEFAULT_CONFIG)
+        resp.raise_for_status()
+        return resp.json()
 
 
 def _apply_env_overrides(config: dict) -> dict:
@@ -75,7 +83,8 @@ async def load_ai_config() -> dict:
     now = time.monotonic()
     if _cache is not None and (now - _cache_at) < _CACHE_TTL:
         return _cache
-    data = await asyncio.to_thread(_read_config_sync)
+    raw = await _fetch_config()
+    data = _apply_env_overrides(raw)
     _cache = data
     _cache_at = now
     return data