Add interactive release search (M6)

Release listing and grab in the shared arr client, a full-screen release
list (sort, hide rejected, rejection reasons, confirmation before grabbing
rejected releases; Usenet only), and a season/episode picker for Sonarr.
Overlays are now a stack so dialogs can open above the release list.
Add a fake Newznab indexer to the dev setup.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

dev/README.md

@@ -35,3 +35,18 @@ curl -H "X-Api-Key: devradarrapikey00000000000000000" -H 'Content-Type: applicat
   -d '{"title":"The.Matrix.1999.1080p.BluRay.x264-DEV","downloadUrl":"http://host.containers.internal:19191/some.nzb","protocol":"usenet","publishDate":"2026-01-01T00:00:00Z"}' \
   http://127.0.0.1:17878/api/v3/release/push
 ```
+
+## Interactive search without a real indexer
+
+`dev/fake-indexer.py` is a tiny Newznab indexer that returns a fixed set of releases for "The Matrix (1999)"
+and "Breaking Bad"; Radarr/Sonarr still do their own parsing and approve/reject decisions. Its NZBs are
+dummies, so grabbed releases just sit in the SABnzbd queue.
+
+```sh
+python3 dev/fake-indexer.py &    # listens on :19292
+dev/add-indexer.sh               # registers it in the dev Radarr and Sonarr
+```
+
+Add the movie / series to the dev instances first (e.g. from the TUI), then press `i` on it.
+To test with a real indexer, add it in the dev Radarr/Sonarr web UI (Settings, Indexers) instead of pasting
+credentials anywhere else.