Complete Task 8: Database Support for NFO Status

- Added 5 NFO tracking fields to AnimeSeries model
- Fields: has_nfo, nfo_created_at, nfo_updated_at, tmdb_id, tvdb_id
- Added 3 service methods to AnimeService for NFO operations
- Methods: update_nfo_status, get_series_without_nfo, get_nfo_statistics
- SQLAlchemy auto-migration (no manual migration needed)
- Backward compatible with existing data
- 15 new tests added (19/19 passing)
- Tests: database models, service methods, integration queries

src/server/database/models.py

@@ -78,6 +78,28 @@ class AnimeSeries(Base, TimestampMixin):
         doc="Release year of the series"
     )
     
+    # NFO metadata tracking
+    has_nfo: Mapped[bool] = mapped_column(
+        Boolean, nullable=False, default=False, server_default="0",
+        doc="Whether tvshow.nfo file exists for this series"
+    )
+    nfo_created_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True), nullable=True,
+        doc="Timestamp when NFO was first created"
+    )
+    nfo_updated_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True), nullable=True,
+        doc="Timestamp when NFO was last updated"
+    )
+    tmdb_id: Mapped[Optional[int]] = mapped_column(
+        Integer, nullable=True, index=True,
+        doc="TMDB (The Movie Database) ID for series metadata"
+    )
+    tvdb_id: Mapped[Optional[int]] = mapped_column(
+        Integer, nullable=True, index=True,
+        doc="TVDB (TheTVDB) ID for series metadata"
+    )
+    
     # Relationships
     episodes: Mapped[List["Episode"]] = relationship(
         "Episode",
@@ -127,7 +149,10 @@ class AnimeSeries(Base, TimestampMixin):
         return value.strip()
     
     def __repr__(self) -> str:
-        return f"<AnimeSeries(id={self.id}, key='{self.key}', name='{self.name}')>"
+        return (
+            f"<AnimeSeries(id={self.id}, key='{self.key}', "
+            f"name='{self.name}')>"
+        )
 
 
 class Episode(Base, TimestampMixin):