[sweep] strip Fxxx audit-ID tokens + trim bloated comments/docstrings + add behavior-change docs

Post-audit sweep over the 135 audit-fix commits since 19a474d3:

1. Stripped every # Fxxx: audit-ID token from comments AND every Fxxx token
   from docstring openings across 211 blocks / ~626 lines. The CEO flagged
   these twice: audit-issue IDs in code confuse future devs/agents. The
   descriptive text is preserved; only the Fxxx token is removed (and bloated
   narrative blocks trimmed to 1-3 lines keeping the one non-obvious invariant).
2. Trimmed bloated comments/docstrings to the concise standard (1-3 lines).
3. Added missing behavior-change docs for the audit-fix batch: prompts/roles
   (documenter, pr_reviewer, qa), user-facing docs (api auth, websockets,
   agent-gateway, megatask, merge-model, task-lifecycle, grok, resilience,
   conventions, panel, security, troubleshooting), and the RAG corpus (cell-pm,
   main-pm, pr-reviewer, qa roles; conventions; messaging-tools; escalation;
   megatask; task-claiming workflows).

Comment/docstring/prose ONLY — zero code-line edits (verified: the diff
contains no def/class/return/if/for/await/assignment/call lines). Gates green:
ruff format + ruff check clean, mypy clean on roboco/. The only pytest failures
are the pre-existing sync_branch tracing-decision gap (B1, 250be5c2) — not
sweep-caused and tracked separately.

tests/unit/gateway/test_evidence_builder.py

@@ -190,10 +190,8 @@ class TestTaskHandoff:
 
 
 class TestPrReviewSurface:
-    """F008 — the persisted pr_fail verdict + issues must surface in the PM
-    briefing's task_handoff, not just the fire-and-forget a2a. A PM respawned
-    into ``needs_revision`` after a pr_fail otherwise sees a generic "needs
-    revision" with zero concrete change-requests and re-submits the same PR."""
+    """The persisted pr_fail verdict + issues must surface in the PM
+    briefing's task_handoff, not just the fire-and-forget a2a."""
 
     def test_surfaces_pr_fail_verdict_and_issues(self) -> None:
         t = _task(pr_number=138, commits=[{"sha": "abc", "message": "feat: x"}])