Floatplane channel plugin for Jellyfin 10.10.x: browse, HLS proxy, cookie session, CI release

- IChannel: creators -> sub-channels -> video posts (public listing API, search mapped)
- IRequiresMediaInfoCallback -> signed proxy URLs; stream controller rewrites HLS so the
  AES-128 key is fetched server-side with the session cookie, segments stay on the CDN
- delivery/info cached per token lifetime and throttled (~2/min)
- config page: paste sails.sid + validate, extra creators, quality, search test
- scripts/package.sh -> plugin folder + zip + md5 + manifest.json; Gitea release workflow
- research docs, HAR analysis (HAR itself gitignored), install-pi5.sh

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,16 @@
+build/
+# Captured browser sessions contain the Floatplane password, session JWTs and e-mail — never commit
+doc/har/*.har
+*.har
+# .NET
+bin/
+obj/
+*.user
+*.suo
+.vs/
+# plugin packaging / local test server
+dist/
+.jellyfin-test/
+# secrets
+.env
+*.local.json