startServer spawns the daemon detached + unref'd, then polls health for a
fixed budget. On a loaded machine the budget can elapse in the gap between
the loop's last tick and the daemon becoming ready — the CLI reported
"Server failed to start within Ns" while the very next `browse status`
showed a healthy server. Add a final readState()+isServerHealthy() re-check
before the timeout throw, and make the budget env-overridable via
BROWSE_START_TIMEOUT (BROWSE_* tunable convention). Structural + behavioral
tests pin both invariants.
Closes#1846.
Contributed by @harjothkhara (PR #1847).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>