Wire Requests approval into Radarr/Sonarr with live download status

Admin can now Approve a pending request as Movie or TV, which looks up
the title via Radarr/Sonarr's own lookup API, adds the best match with
search-on-add enabled, and tracks the resulting radarr_id/sonarr_id on
the request. A live status line (searching/queued/downloading/downloaded,
polled every 15s) shows next to each approved request.

backend/models.py

@@ -191,6 +191,10 @@ class RequestUpdate(BaseModel):
     status: str
 
 
+class RequestApprove(BaseModel):
+    content_type: str  # "movie" | "tv"
+
+
 class MovieRequest(BaseModel):
     model_config = ConfigDict(extra="ignore")
     id: str = Field(default_factory=lambda: str(uuid.uuid4()))
@@ -199,7 +203,12 @@ class MovieRequest(BaseModel):
     title: str
     year: Optional[int] = None
     notes: str = ""
-    status: str = "pending"
+    status: str = "pending"  # pending | approved | fulfilled | rejected
+    content_type: Optional[str] = None  # movie | tv, set once approved
+    radarr_id: Optional[int] = None
+    sonarr_id: Optional[int] = None
+    matched_title: Optional[str] = None
+    matched_year: Optional[int] = None
     created_at: str = Field(default_factory=_now_iso)