docs: explain intent-specific worker pools

[pilipilisbot]

Summary

• document intent-specific executor pools for review-only and work-allowed capacity
• expose GITHUB_AGENT_BRIDGE_WORK_INTENT in the packaged systemd env/unit so admins can configure worker specialization from the env file
• clarify that worker claim filters do not change policy classification, prompts, or write permission

Follow-up to #159 / #158.

Tests

• ../github-agent-bridge-issue158/.venv/bin/python -m pytest tests/test_manual_enqueue_cli.py tests/test_queue.py -q -> 28 passed
• ../github-agent-bridge-issue158/.venv/bin/python - <<PY ... parser smoke test for all and comma-separated intents -> passed

[ecarreras]

@pilipilisbot el work_intent permet els dos tipus?

[pilipilisbot]

Sí. Cada job té un únic work_intent (review_only o work_allowed), però el filtre de l'executor pot acceptar-ne més d'un.

A la pràctica:

• sense --work-intent, o amb --work-intent all, l'executor reclama tots dos tipus;
• --work-intent review_only,work_allowed també accepta tots dos tipus;
• --work-intent review_only o --work-intent work_allowed limita aquell pool a només un tipus.

Això només afecta el claim de jobs pendents. No reclassifica la notificació ni dona permisos d'escriptura a un job review_only.

[pilipilisbot]

Verified the merged PR state on origin/main at cc3b213. The docs/systemd changes for GITHUB_AGENT_BRIDGE_WORK_INTENT are present, including the all/omitted default and repeated/comma-separated intent filters, and the focused tests pass with .venv/bin/python -m pytest tests/test_manual_enqueue_cli.py tests/test_queue.py -q (29 passed).\n\nNo code/docs update was needed from this follow-up because the triggering event was the merge/close event and the PR branch has already been deleted.