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>

doc/research/reference-sources/fn_PKCEManager.kt

@@ -0,0 +1,22 @@
+package com.coulterpeterson.floatnative.data
+
+import android.util.Base64
+import java.security.MessageDigest
+import java.security.SecureRandom
+
+object PKCEManager {
+
+    fun generateCodeVerifier(): String {
+        val secureRandom = SecureRandom()
+        val codeVerifier = ByteArray(32)
+        secureRandom.nextBytes(codeVerifier)
+        return Base64.encodeToString(codeVerifier, Base64.URL_SAFE or Base64.NO_WRAP or Base64.NO_PADDING)
+    }
+
+    fun generateCodeChallenge(verifier: String): String {
+        val bytes = verifier.toByteArray(Charsets.US_ASCII)
+        val md = MessageDigest.getInstance("SHA-256")
+        val digest = md.digest(bytes)
+        return Base64.encodeToString(digest, Base64.URL_SAFE or Base64.NO_WRAP or Base64.NO_PADDING)
+    }
+}