x07-rr-pipes-smoke

Reference implementation for Prompt 7 in docs/agent/readiness-checks.md.

• Prompt: PROMPT.md
• Hydrate deps: x07 pkg lock --project x07.json
• Run (record): x07 run --profile os_record --allow-host 127.0.0.1:18080 -- <args...>
• Run (replay): x07 run --profile rr_replay --fixture-rr-dir .x07_rr -- <args...>
• Bundle (replay): x07 bundle --profile rr_replay --out dist/rr-replay
• Tests: x07 test --manifest tests/tests.json