chore: mark fc-004 external LLM integration as resolved

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plans/index.json

@@ -124,8 +124,9 @@
     },
     "gleaming-routing-mercury": {
       "title": "External LLM integration",
-      "status": "pending",
+      "status": "implemented",
       "created": "2026-01-08",
+      "implemented": "2026-01-08",
       "category": "feature",
       "notes": "fc-004 - Cloud API integration via opencode/gemini CLIs with session toggle"
     }

state/future-considerations.json

@@ -38,10 +38,11 @@
       "title": "External LLM integration",
       "description": "Support for non-Claude models in the agent system",
       "priority": "medium",
-      "status": "planned",
+      "status": "resolved",
       "created": "2024-12-28",
+      "resolved": "2026-01-08",
       "plan": "gleaming-routing-mercury",
-      "notes": "Cloud APIs via subscription (Copilot, Z.AI, Gemini). Uses opencode/gemini CLIs. Session toggle for external-only mode."
+      "notes": "Implemented via opencode CLI. Models: github-copilot/gpt-5.2, zai-coding-plan/glm-4.7, etc. Toggle via /pa --external or natural language."
     },
     {
       "id": "fc-005",