fix(server): delete ServerConfig.idleTimeoutMs + chromiumProfile — documented, never read

Both fields carried JSDoc asserting embedder behavior that did not exist:
the idle check reads the module-level IDLE_TIMEOUT_MS env constant, and both
resolveChromiumProfile() call sites pass no argument. Worse than absent — an
embedder passing idleTimeoutMs: 5000 silently got 30 minutes.

Wiring them honestly is impossible today: the idle timer, activity state, and
shutdown target are module-global, so a per-factory value would lie for any
process running more than one handler. Deleted instead, with a ServerConfig
note pointing at the deferred singleton/route-table refactor where real
support belongs. BROWSE_IDLE_TIMEOUT and CHROMIUM_PROFILE env remain the
honest knobs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

browse/src/config.ts

@@ -169,7 +169,8 @@ export function resolveGstackHome(): string {
  * Resolve the Chromium profile directory.
  *
  * Resolution order:
- *   1. `explicit` arg (passed via ServerConfig.chromiumProfile by embedders)
+ *   1. `explicit` arg (no production caller passes one today; kept for
+ *      direct programmatic use)
  *   2. CHROMIUM_PROFILE env (used by gbrowser's gbd per-workspace)
  *   3. <resolveGstackHome()>/chromium-profile (default)
  */

browse/src/server.ts

@@ -190,14 +190,16 @@ export interface ServerConfig {
   authToken: string;
   /** Local listener port. Used in /welcome URL + state-file. */
   browsePort: number;
-  /** Idle shutdown timeout. Default 30 min. */
-  idleTimeoutMs: number;
   /** Result of resolveConfig() — stateDir, auditLog, stateFile. */
   config: ReturnType<typeof resolveConfig>;
   /** Pre-launched BrowserManager. Caller owns lifecycle. */
   browserManager: BrowserManager;
-  /** Optional Chromium profile path override. Resolved by resolveChromiumProfile(). */
-  chromiumProfile?: string;
+  // NOTE: per-factory idleTimeoutMs and chromiumProfile were deleted — they
+  // were documented but never read (the idle timer, activity state, and
+  // shutdown target are module-global, so per-factory wiring would lie for
+  // any embedder running >1 handler). Real support belongs to the deferred
+  // server.ts singleton/route-table refactor. Until then: BROWSE_IDLE_TIMEOUT
+  // and CHROMIUM_PROFILE env are the honest knobs.
   /** Caller-owned. shutdown() does NOT call xvfb.stop(); caller is responsible. */
   xvfb?: XvfbHandle | null;
   /** Caller-owned. shutdown() does NOT call proxyBridge.close(); caller is responsible. */
@@ -283,7 +285,6 @@ export function resolveConfigFromEnv(): Omit<ServerConfig, 'browserManager' | 's
     // embedder can't ship a BOM/zero-width as the bearer secret.
     authToken: sanitizeAuthToken(process.env.AUTH_TOKEN) || crypto.randomUUID(),
     browsePort: parseInt(process.env.BROWSE_PORT || '0', 10),
-    idleTimeoutMs: parseInt(process.env.BROWSE_IDLE_TIMEOUT || '1800000', 10),
     config: resolveConfig(),
   };
 }