feat: robust scraping DSL and health monitoring (Phase 2)

- Implemented YAML-driven GenericScraper for resilient scraping
- Added ProvidersManager to manage scraper health and active providers
- Modernized unified search with systematic Kitsu metadata enrichment
- Integrated automated health checks in the scheduler
- Added comprehensive tests for scraping DSL and provider health

app/downloaders/providers_config/animesama.yaml

@@ -0,0 +1,24 @@
+name: "Anime-Sama"
+id: "animesama"
+base_url: "https://anime-sama.fr"
+mirrors:
+  - "https://anime-sama.si"
+  - "https://anime-sama.co"
+
+search:
+  path: "/search?q={query}"
+  container_selector: ".result-item"
+  title_selector: "h3"
+  url_selector: "a"
+  image_selector: "img"
+
+episodes:
+  container_selector: "#episodes-list"
+  item_selector: ".episode-item"
+  # Logic for Anime-Sama can be complex, we'll handle custom logic in GenericScraper 
+  # but keep common selectors here.
+  player_iframe_selector: "iframe#player"
+
+metadata:
+  synopsis_selector: ".synopsis"
+  genres_selector: ".genres .genre"