feat(nfo): implement NFO diagnostics and repair

- Add NFO API endpoints: diagnostics, repair, validate, needs-repair
- Create /settings/nfo page with full NFO management UI
- Add NFO status section to edit modal with repair functionality
- Add anime details API for edit modal pre-fill data
- Fix auth test fixtures in test_nfo_diagnostics_repair.py

Implements NFO diagnostics when editing anime series via right-click menu.
Users can now check NFO status, see missing tags, and repair NFOs
directly from the edit modal or the dedicated NFO settings page.

src/server/models/anime.py

@@ -133,21 +133,85 @@ class SearchResult(BaseModel):
         )
     )
     title: str = Field(..., description="Series title")
-    folder: Optional[str] = Field(
-        None,
-        description=(
-            "Series folder name on disk (metadata only) "
-            "(e.g., 'Attack on Titan (2013)'). For display/filesystem ops only."
-        )
-    )
-    snippet: Optional[str] = Field(None, description="Short description or snippet")
-    thumbnail: Optional[HttpUrl] = Field(None, description="Thumbnail image URL")
-    score: Optional[float] = Field(None, ge=0.0, le=1.0, description="Search relevance score (0-1)")
 
-    @field_validator('key', mode='before')
-    @classmethod
-    def normalize_key(cls, v: str) -> str:
-        """Normalize key to lowercase."""
-        if isinstance(v, str):
-            return v.lower().strip()
-        return v
+
+class AnimeDetailsResponse(BaseModel):
+    """Detailed response model for a single anime series with all metadata.
+    
+    Used by the edit modal to pre-fill form fields with existing data.
+    
+    Attributes:
+        key: Unique series identifier
+        name: Display name
+        folder: Filesystem folder name
+        year: Release year
+        status: Show status (Continuing, Ended)
+        plot: Plot description
+        genres: List of genres
+        studio: List of studios
+        premiered: Premiere date
+        rating: Rating value (0-10)
+        rating_votes: Number of votes
+        tmdb_id: TMDB ID
+        tvdb_id: TVDB ID
+        has_nfo: Whether NFO file exists
+        nfo_created_at: NFO creation timestamp
+        nfo_updated_at: NFO update timestamp
+    """
+
+    key: str = Field(..., description="Unique series identifier")
+    name: str = Field(..., description="Display name")
+    folder: Optional[str] = Field(None, description="Filesystem folder name")
+    year: Optional[int] = Field(None, ge=1900, le=2100, description="Release year")
+    status: Optional[str] = Field(None, description="Show status (Continuing, Ended)")
+    plot: Optional[str] = Field(None, description="Plot description")
+    genres: List[str] = Field(default_factory=list, description="List of genres")
+    studio: List[str] = Field(default_factory=list, description="List of studios")
+    premiered: Optional[str] = Field(None, description="Premiere date (YYYY-MM-DD)")
+    rating: Optional[float] = Field(None, ge=0, le=10, description="Rating value (0-10)")
+    rating_votes: Optional[int] = Field(None, ge=0, description="Number of votes")
+    tmdb_id: Optional[int] = Field(None, description="TMDB ID")
+    tvdb_id: Optional[int] = Field(None, description="TVDB ID")
+    has_nfo: bool = Field(False, description="Whether NFO file exists")
+    nfo_created_at: Optional[str] = Field(None, description="NFO creation timestamp")
+    nfo_updated_at: Optional[str] = Field(None, description="NFO update timestamp")
+
+    class Config:
+        json_schema_extra = {
+            "example": {
+                "key": "attack-on-titan",
+                "name": "Attack on Titan",
+                "folder": "Attack on Titan (2013)",
+                "year": 2013,
+                "status": "Ended",
+                "plot": "Humans fight against giant humanoid Titans.",
+                "genres": ["Animation", "Action", "Drama"],
+                "studio": ["Wit Studio", "MAPPA"],
+                "premiered": "2013-04-07",
+                "rating": 9.0,
+                "rating_votes": 500000,
+                "tmdb_id": 1429,
+                "tvdb_id": 267440,
+                "has_nfo": True,
+                "nfo_created_at": "2025-01-15T10:30:00Z",
+                "nfo_updated_at": "2025-01-15T10:30:00Z",
+            }
+        }
+
+
+class TMDBSearchResult(BaseModel):
+    """TMDB search result for auto-lookup functionality.
+    
+    Attributes:
+        tmdb_id: TMDB ID of the matched series
+        title: Title from TMDB
+        year: Release year
+        overview: Short description
+        vote_average: TMDB rating
+    """
+
+    tmdb_id: int = Field(..., description="TMDB ID")
+    title: str = Field(..., description="Title from TMDB")
+    year: Optional[int] = Field(None, description="Release year")
+    overview: Optional[str] = Field(None, description="Short description")
+    vote_average: Optional[float] = Field(None, description="TMDB rating")