docs: nomos agent code review — mark all fixes done except deferred C1

Every finding from the review is now implemented and verified live:
A1 (3919ec3), B1+B2 (c5ffaec), A3 (926969a), D1-D3 (76f7630), A2 (c390164),
B3 (6d4f6de), F1 (11c18e8). C1 (nomos gateway has no authentication) remains
explicitly deferred per operator instruction. Kept in plans/ (not moved to
done/) since C1 is still open, matching how other partially-complete plans
in this index are tracked.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

plans/index.md

@@ -13,7 +13,7 @@ went sideways, open an investigation.
 | 2026-07-08 | [Control room web UI](2026-07-08-control-room-webui.md) | In Progress |
 | 2026-07-08 | [Liveness, drift, and UX cohesion](2026-07-08-liveness-drift-and-ux-cohesion.md) | In Progress — Phase 5 deferred |
 | 2026-07-10 | [General gated execution: unlimited actions, gated by risk](2026-07-10-general-gated-execution.md) | In Progress — enum retirement + auto-act revival still open |
-| 2026-07-11 | [Nomos agent code review: gaps and improvement plan](2026-07-11-nomos-agent-code-review.md) | Planned |
+| 2026-07-11 | [Nomos agent code review: gaps and improvement plan](2026-07-11-nomos-agent-code-review.md) | In Progress — only C1 (unauthenticated nomos gateway) still open, deferred |
 
 ## Done