feat(cli): add startup performance profiler (#3219)
Add a lightweight startup profiler activated via QWEN_CODE_PROFILE_STARTUP=1.
When enabled, collects performance.now() timestamps at 7 key phases in main()
and writes a JSON report to ~/.qwen/startup-perf/. Also records
process.uptime() at T0 to capture module loading time not covered by
checkpoint-based measurement.
Key design decisions:
- Only profiles inside sandbox child process to avoid duplicate reports
- initStartupProfiler() is idempotent (resets state on each call)
- Filename uses report.sessionId for consistency with JSON content
- Zero overhead when disabled (single env var check)
Initial measurement: module loading ~1342ms (94%), main() ~85ms (6%),
confirming barrel exports and eager dependency loading as primary
optimization targets for #3011.
Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>
Add global uncaught exception handler to suppress known race condition
in @lydell/node-pty where a deferred resize fires after the pty process
has already exited on Windows.
Tracking bug: https://github.com/microsoft/node-pty/issues/827
Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>
