What does this PR do?

dump_api_request_debug() in agent/agent_runtime_helpers.py writes the request debug dump with bare write_text(). If the process is killed mid-write (OOM, SIGKILL during a bad API call storm), the dump file is left partially written — this is the file most likely to be examined post-mortem, so corruption here hurts diagnosis of the very failures it was meant to capture.

atomic_json_write is already imported from utils at the top of the file but unused here.

Type of Change

• Bug fix

Changes Made

• Replaced 4-line write_text(json.dumps(...)) block with a single atomic_json_write(dump_file, dump_payload) call
• No behavioral change — same output, same file path, now crash-safe

How to Test

1. Review agent/agent_runtime_helpers.py around line 1065
2. Verify atomic_json_write is now used instead of write_text
3. Run python -m pytest tests/ -q — no regressions expected

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix
• I've tested on my platform: Ubuntu 24.04 (WSL2)

Documentation & Housekeeping

• No documentation changes needed
• Cross-platform considered — no platform-specific impact