test(browse): integration coverage for daemon mismatch + proxy fail-fast

Adds two integration tests that exercise the full process boundary,
not just the module-level wiring.

daemon-mismatch-refuse.test.ts (D2):
- Stubs a healthy state file with a fake configHash and a fake /health
  HTTP server, runs the actual cli.ts binary with a mismatching
  --proxy, asserts exit 1 + 'different config' / 'browse disconnect'
  hint in stderr.
- Same shape with the plain-daemon-meets---headed case.
- Positive case: matching configHash → CLI does NOT emit the mismatch
  hint (regardless of whether the actual command succeeds).

server-proxy-fail-fast.test.ts:
- Starts the rejecting SOCKS5 upstream, spawns server.ts with
  BROWSE_PROXY_URL pointing at it, BROWSE_HEADLESS_SKIP=1 to skip
  Chromium launch.
- Asserts exit 1, 'FAIL upstream' in stderr (testUpstream pre-flight
  ran), no raw credential leakage in any output (redaction works on
  the failure path), and exit within 30s upper bound.

Both tests use the existing spawn-bun-cli pattern from
commands.test.ts so they run on the same CI infrastructure as the
rest of the bun test suite.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

browse/test/server-proxy-fail-fast.test.ts

@@ -0,0 +1,98 @@
+/**
+ * Integration test: server.ts startup fail-fast on bad SOCKS5 upstream.
+ *
+ * Spawns the actual server.ts with BROWSE_PROXY_URL pointing at a port
+ * that listens but rejects every CONNECT. Asserts:
+ *   - exit code 1
+ *   - stderr contains "FAIL upstream" (proof the testUpstream pre-flight ran)
+ *   - stderr does NOT contain raw credentials (proof redaction works on
+ *     the failure path)
+ *   - exits within the 5s budget + retry overhead
+ */
+
+import { describe, test, expect } from 'bun:test';
+import { spawn } from 'child_process';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import * as net from 'net';
+
+async function startRejectingUpstream(): Promise<{ port: number; close: () => Promise<void> }> {
+  // Accepts TCP connections, completes the SOCKS5 username/password auth
+  // handshake by REJECTING (status 0x01), then closes. Our testUpstream()
+  // should retry 3x and exhaust within ~5s.
+  const server = net.createServer((sock) => {
+    sock.once('data', (greeting) => {
+      if (greeting[0] !== 0x05) { sock.destroy(); return; }
+      const methods = greeting.subarray(2, 2 + greeting[1]);
+      if (!methods.includes(0x02)) { sock.write(Buffer.from([0x05, 0xFF])); sock.destroy(); return; }
+      sock.write(Buffer.from([0x05, 0x02]));
+      sock.once('data', () => {
+        // Reject auth (0x01)
+        try { sock.write(Buffer.from([0x01, 0x01])); } catch { /* peer gone */ }
+        sock.destroy();
+      });
+    });
+    sock.on('error', () => sock.destroy());
+  });
+  await new Promise<void>((resolve, reject) => {
+    server.once('error', reject);
+    server.listen(0, '127.0.0.1', () => resolve());
+  });
+  const addr = server.address();
+  if (!addr || typeof addr === 'string') throw new Error('rejecting upstream: bad address');
+  return {
+    port: addr.port,
+    close: () => new Promise((r) => server.close(() => r())),
+  };
+}
+
+describe('server fail-fast on bad SOCKS5 upstream', () => {
+  test('exits 1 with redacted error within budget', async () => {
+    const upstream = await startRejectingUpstream();
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'browse-fail-fast-'));
+    const stateFile = path.join(tmpDir, 'browse.json');
+
+    const serverPath = path.resolve(__dirname, '../src/server.ts');
+    const env: Record<string, string> = {};
+    for (const [k, v] of Object.entries(process.env)) {
+      if (v !== undefined) env[k] = v;
+    }
+    env.BROWSE_STATE_FILE = stateFile;
+    env.BROWSE_PARENT_PID = '0'; // disable watchdog so we can isolate the proxy failure
+    env.BROWSE_HEADLESS_SKIP = '1'; // skip the chromium launch (we only test the proxy gate)
+    env.BROWSE_PROXY_URL = `socks5://baduser:badpass@127.0.0.1:${upstream.port}`;
+
+    const start = Date.now();
+    const result = await new Promise<{ code: number; stdout: string; stderr: string; ms: number }>((resolve) => {
+      const proc = spawn('bun', ['run', serverPath], {
+        timeout: 30000,
+        env,
+      });
+      let stdout = ''; let stderr = '';
+      proc.stdout.on('data', (d) => stdout += d.toString());
+      proc.stderr.on('data', (d) => stderr += d.toString());
+      proc.on('close', (code) => resolve({ code: code ?? 1, stdout, stderr, ms: Date.now() - start }));
+    });
+
+    try {
+      // Expectation 1: exit 1
+      expect(result.code).toBe(1);
+      // Expectation 2: stderr names the failure mode and references the upstream
+      const combined = result.stdout + result.stderr;
+      expect(combined).toMatch(/FAIL upstream/);
+      // Expectation 3: redaction. Raw 'baduser' and 'badpass' must NEVER
+      // appear in any output, even on the failure path.
+      expect(combined).not.toContain('baduser');
+      expect(combined).not.toContain('badpass');
+      // Expectation 4: budget. testUpstream caps at 5s plus a small amount
+      // of script startup overhead (~3-5s for `bun run`). Cap at 30s as a
+      // generous upper bound so the assertion is meaningful but not flaky.
+      expect(result.ms).toBeLessThan(30000);
+    } finally {
+      await upstream.close();
+      try { fs.unlinkSync(stateFile); } catch { /* ignore */ }
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+  }, 60000);
+});