feat(storage): implement NAS content storage with read/write capabilities

feat(docker): configure NAS content and EPUB source directories in docker-compose

feat(migrations): add tables for SourceAsset, ImportJob, ChapterContentRef, and AssetNovelMapping

feat(scripts): create backfill script for populating ChapterContentRef from MongoDB chapters

app/auth.py

@@ -121,7 +121,10 @@ async def resolve_current_user(db: AsyncSession, request: Request) -> dict[str,
     return await _get_user_from_session_cookie(db, request)
 
 
-async def require_current_user(db: AsyncSession, request: Request) -> dict[str, Any]:
+async def require_current_user(
+    request: Request,
+    db: AsyncSession = Depends(get_db_session),
+) -> dict[str, Any]:
     user = await resolve_current_user(db, request)
     if not user:
         raise HTTPException(status_code=401, detail="Unauthorized")

app/config.py

@@ -20,6 +20,9 @@ class Settings(BaseSettings):
     r2_secret_access_key: str = ""
     r2_bucket_name: str = ""
     r2_public_base_url: str = ""
+    nas_content_root: str = "./data/content"
+    epub_source_root: str = "./data/epub-source"
+    chapter_content_mode: str = "nas_first"  # nas_first | mongo_first
 
     deepseek_key: str = ""
     deepseek_model: str = "deepseek-chat"

app/storage.py

@@ -0,0 +1,33 @@
+from __future__ import annotations
+
+import hashlib
+from pathlib import Path
+
+from app.config import settings
+
+
+class NasContentStorage:
+    def __init__(self, root_dir: str):
+        self.root = Path(root_dir).resolve()
+        self.root.mkdir(parents=True, exist_ok=True)
+
+    def _resolve(self, href: str) -> Path:
+        rel = href.strip().lstrip("/")
+        target = (self.root / rel).resolve()
+        if self.root not in target.parents and target != self.root:
+            raise ValueError("Invalid storage href")
+        return target
+
+    def read_text(self, href: str) -> str:
+        path = self._resolve(href)
+        return path.read_text(encoding="utf-8")
+
+    def write_text(self, href: str, content: str) -> dict[str, str | int]:
+        path = self._resolve(href)
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text(content, encoding="utf-8")
+        digest = hashlib.sha256(content.encode("utf-8")).hexdigest()
+        return {"href": href, "sha256": digest, "size": len(content.encode("utf-8"))}
+
+
+storage = NasContentStorage(settings.nas_content_root)