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

tools/rtmp-server.js

@@ -0,0 +1,82 @@
+#!/usr/bin/env node
+/**
+ * Local RTMP test server for LCK Control streaming development.
+ *
+ * Usage:
+ *   node tools/rtmp-server.js
+ *
+ * Then configure a stream plan destination with:
+ *   RTMP URL: rtmp://<PC_IP>:1935/live
+ *   Stream Key: test
+ *
+ * View the stream:
+ *   ffplay rtmp://localhost:1935/live/test
+ *   or open http://localhost:8000/live/test.flv in a browser/VLC
+ */
+const NodeMediaServer = require('node-media-server');
+const { spawn } = require('child_process');
+
+const viewers = new Map(); // streamPath -> child process
+
+const config = {
+  rtmp: {
+    port: 1935,
+    chunk_size: 60000,
+    gop_cache: true,
+    ping: 30,
+    ping_timeout: 60,
+  },
+  http: {
+    port: 8000,
+    allow_origin: '*',
+  },
+};
+
+const nms = new NodeMediaServer(config);
+
+nms.on('prePublish', (session) => {
+  const streamPath = session.publishStreamPath || session.streamPath || '';
+  const id = session.id || '';
+  console.log(`[stream] Client publishing: ${streamPath} (session ${id})`);
+  const url = `rtmp://localhost:1935${streamPath}`;
+  if (streamPath && !viewers.has(streamPath)) {
+    console.log(`[ffplay] Launching viewer for ${url}`);
+    const child = spawn('ffplay', ['-window_title', streamPath, url], {
+      stdio: 'ignore',
+      detached: true,
+    });
+    child.unref();
+    child.on('exit', () => viewers.delete(streamPath));
+    viewers.set(streamPath, child);
+  }
+});
+
+nms.on('donePublish', (session) => {
+  const streamPath = session.publishStreamPath || session.streamPath || '';
+  const id = session.id || '';
+  console.log(`[stream] Client stopped: ${streamPath} (session ${id})`);
+  const child = viewers.get(streamPath);
+  if (child) {
+    child.kill();
+    viewers.delete(streamPath);
+  }
+});
+
+nms.on('prePlay', (session) => {
+  const streamPath = session.playStreamPath || session.streamPath || '';
+  const id = session.id || '';
+  console.log(`[viewer] Viewer connected: ${streamPath} (session ${id})`);
+});
+
+nms.on('donePlay', (session) => {
+  const streamPath = session.playStreamPath || session.streamPath || '';
+  const id = session.id || '';
+  console.log(`[viewer] Viewer disconnected: ${streamPath} (session ${id})`);
+});
+
+nms.run();
+
+console.log('\n--- LCK Control Test RTMP Server ---');
+console.log('RTMP:     rtmp://localhost:1935/live/test');
+console.log('HTTP-FLV: http://localhost:8000/live/test.flv');
+console.log('View:     ffplay rtmp://localhost:1935/live/test\n');