Update PVideoDl to support custom download strategies and enhance cookie handling. Added new downloader registration system, updated README for clarity on downloaders, and introduced cookies configuration in settings. Frontend now includes a dedicated tab for download strategies and API endpoints for listing them.

app/models.py

@@ -46,6 +46,15 @@ class CreateDownloads(BaseModel):
     urls: list[str] = Field(default_factory=list, min_length=1)
 
 
+class DownloaderInfo(BaseModel):
+    """Зарегистрированная стратегия скачивания — для страницы «Загрузчики»."""
+
+    name: str
+    kind: str  # "direct" | "extractor" | "fallback"
+    priority: int
+    description: str | None = None
+
+
 # --- События шины (то, что улетает в SSE) ---