Custom RTMP saved accounts, RTMP test server, composition pipeline

- Backend: POST /providers/accounts/custom-rtmp to save reusable RTMP servers
- Backend: Encrypt rtmpUrl/streamKey in existing token fields, decrypt on GET
- Backend: Skip token revocation on DELETE for CUSTOM_RTMP accounts
- Backend: Decrypt CUSTOM_RTMP credentials into destinations on plan create/update
- Android: Add rtmpUrl/streamKey to LinkedAccount entity + shared parcelable (Room v6)
- Android: Add Custom RTMP dialog in AccountsScreen, auto-fill in plan destination picker
- Android: Handle CUSTOM_RTMP accounts in CreatePlanViewModel.loadExistingPlan
- Add local RTMP test server (tools/rtmp-server.js) with auto-ffplay on publish
- Add composition pipeline native code

app/src/main/java/com/omixlab/lckcontrol/service/LckControlService.kt

@@ -302,15 +302,28 @@ class LckControlService : Service() {
 
     // ── Auth logic ──────────────────────────────────────────
 
+    private fun extractJwtSub(jwt: String): String? {
+        return try {
+            val parts = jwt.split(".")
+            if (parts.size < 2) return null
+            val payload = String(android.util.Base64.decode(parts[1], android.util.Base64.URL_SAFE or android.util.Base64.NO_WRAP))
+            org.json.JSONObject(payload).optString("sub", "").ifEmpty { null }
+        } catch (_: Exception) { null }
+    }
+
     private suspend fun doAutoLogin() {
         // Try token refresh first
         val refreshToken = tokenStore.getRefreshToken()
+        val oldJwt = tokenStore.getJwt()
+        val oldSub = oldJwt?.let { extractJwtSub(it) }
+        Log.d(TAG, "doAutoLogin: hasRefreshToken=${refreshToken != null}, currentUserId=$oldSub")
         if (refreshToken != null) {
             Log.d(TAG, "Attempting token refresh...")
             try {
                 val response = apiService.refreshSession(RefreshRequest(refreshToken))
+                val newSub = extractJwtSub(response.accessToken)
+                Log.d(TAG, "Token refresh successful, userId=$newSub (was $oldSub)")
                 tokenStore.saveSession(response.accessToken, response.refreshToken)
-                Log.d(TAG, "Token refresh successful")
                 broadcastAuthStateChanged(true)
                 return
             } catch (e: Exception) {
@@ -320,6 +333,7 @@ class LckControlService : Service() {
         }
 
         // Full Quest SDK login
+        Log.d(TAG, "Starting Quest SDK login (previous userId=$oldSub)")
         doQuestLogin()
     }
 
@@ -358,8 +372,9 @@ class LckControlService : Service() {
             )
         )
 
+        val loginSub = extractJwtSub(response.accessToken)
         tokenStore.saveSession(response.accessToken, response.refreshToken)
-        Log.d(TAG, "Quest SDK login successful")
+        Log.d(TAG, "Quest SDK login successful, userId=$loginSub")
         broadcastAuthStateChanged(true)
     }