fix texthooker gate, overlay fallback, and control server byte limit

- gate --texthooker flag on both CLI useTexthooker arg and plugin texthookerEnabled
- remove erroneous return that blocked legacy app startup fallback after control command failure
- fix open-config-settings to only skipRender when window actually opened
- track raw byte count for accurate 64KB limit in app control server

src/main.ts

@@ -3077,10 +3077,14 @@ const openFirstRunSetupWindowHandler = createOpenFirstRunSetupWindowHandler({
       return;
     }
     if (submission.action === 'open-config-settings') {
-      firstRunSetupMessage = openConfigSettingsWindow()
+      const opened = openConfigSettingsWindow();
+      firstRunSetupMessage = opened
         ? 'Opened SubMiner settings.'
         : 'SubMiner settings are unavailable.';
-      return { skipRender: true };
+      if (opened) {
+        return { skipRender: true };
+      }
+      return;
     }
     if (submission.action === 'refresh') {
       const snapshot = await firstRunSetupService.refreshStatus('Status refreshed.');

src/main/runtime/app-control-server.test.ts

@@ -45,3 +45,31 @@ test('app control server dispatches argv requests and replies ok', async () => {
     fs.rmSync(dir, { recursive: true, force: true });
   }
 });
+
+test('app control server rejects requests larger than 64KB by UTF-8 byte length', async () => {
+  if (process.platform === 'win32') return;
+
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-control-test-'));
+  const socketPath = path.join(dir, 'control.sock');
+  const received: string[][] = [];
+  const server = startAppControlServer({
+    socketPath,
+    platform: 'linux',
+    handleArgv: (argv) => {
+      received.push(argv);
+    },
+  });
+
+  try {
+    await waitForSocketPath(socketPath);
+    const result = await sendAppControlCommand(Array.from({ length: 4 }, () => 'あ'.repeat(6000)), {
+      socketPath,
+    });
+
+    assert.deepEqual(result, { ok: false, error: 'App control request too large' });
+    assert.deepEqual(received, []);
+  } finally {
+    server.close();
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});

src/main/runtime/app-control-server.ts

@@ -44,12 +44,14 @@ export function startAppControlServer(options: AppControlServerOptions): AppCont
 
   const server = net.createServer((socket) => {
     let buffer = '';
+    let byteCount = 0;
     let handled = false;
 
     socket.on('data', (chunk) => {
       if (handled) return;
+      byteCount += chunk.length;
       buffer += chunk.toString('utf8');
-      if (buffer.length > 65536) {
+      if (byteCount > 65536) {
         handled = true;
         writeResponse(socket, { ok: false, error: 'App control request too large' });
         return;