Pipe MCP subprocess stderr to logger and fix bin lookup key

Two review followups:
- Consume the piped stderr from @playwright/mcp so browser-launch
  failures surface in our own logs (was set to "pipe" but never read).
- Drop the wrong ["mcp-server-playwright"] lookup; the actual bin key
  is "playwright-mcp". Falling through Object.values worked but was
  dead code.

src/agent/playwright-mcp.ts

@@ -43,7 +43,7 @@ export interface McpCallResult {
 
 export async function createPlaywrightMcpBridge(opts: PlaywrightMcpOptions): Promise<PlaywrightMcpBridge> {
   const argv = buildArgs(opts);
-  const factory = opts.clientFactory ?? defaultClientFactory;
+  const factory = opts.clientFactory ?? ((a) => defaultClientFactory(a, opts.logger));
   const client = await factory(argv);
   const { tools: mcpTools } = await client.listTools();
   const tools: CustomTools = mcpTools.map((t) => wrapTool(t, client));
@@ -83,13 +83,13 @@ function buildArgs(opts: PlaywrightMcpOptions): string[] {
   return args;
 }
 
-async function defaultClientFactory(argv: string[]): Promise<McpClientLike> {
+async function defaultClientFactory(argv: string[], logger: Logger): Promise<McpClientLike> {
   // Resolve the bin from our own node_modules so we never depend on `npx` at
   // runtime and always get the pinned @playwright/mcp version.
   const require = createRequire(import.meta.url);
   const pkgPath = require.resolve("@playwright/mcp/package.json");
   const pkg = require("@playwright/mcp/package.json") as { bin?: string | Record<string, string> };
-  const binField = typeof pkg.bin === "string" ? pkg.bin : pkg.bin?.["mcp-server-playwright"] ?? Object.values(pkg.bin ?? {})[0];
+  const binField = typeof pkg.bin === "string" ? pkg.bin : Object.values(pkg.bin ?? {})[0];
   if (!binField) throw new Error("@playwright/mcp package.json has no bin entry");
   const path = await import("node:path");
   const binAbs = path.resolve(path.dirname(pkgPath), binField);
@@ -101,6 +101,10 @@ async function defaultClientFactory(argv: string[]): Promise<McpClientLike> {
   });
   const client = new Client({ name: "volcanic-secretary", version: "0.1.0" });
   await client.connect(transport);
+  transport.stderr?.on("data", (buf: Buffer | string) => {
+    const line = (typeof buf === "string" ? buf : buf.toString("utf8")).trimEnd();
+    if (line) logger.warn(`playwright mcp: ${line}`);
+  });
   return client as unknown as McpClientLike;
 }