feat: add Guanghu persona continuity skill kernel

Part 3/4 of the recovered Fifth Domain upgrade. Applies the persona continuity skill guard from local source commit 18dfdfd without rewriting remote history.

skills/codex/guanghu-persona-skill-guard/references/intent-state-capsule.schema.json

@@ -0,0 +1,44 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "guanghu.intent-state-capsule/v1",
+  "title": "Guanghu Intent State Capsule",
+  "type": "object",
+  "additionalProperties": false,
+  "required": [
+    "schema",
+    "capsule_id",
+    "human_anchor",
+    "persona_id",
+    "conversation_instance_id",
+    "task_intent",
+    "identity_boundary",
+    "established_facts",
+    "decisions",
+    "rejected_routes",
+    "authorization_state",
+    "current_checkpoint",
+    "next_action",
+    "completion_definition",
+    "evidence",
+    "updated_at"
+  ],
+  "properties": {
+    "schema": {"const": "guanghu.intent-state-capsule/v1"},
+    "capsule_id": {"type": "string", "minLength": 1},
+    "human_anchor": {"type": "string", "minLength": 1},
+    "persona_id": {"type": "string", "minLength": 1},
+    "conversation_instance_id": {"type": "string", "minLength": 1},
+    "task_intent": {"type": "string", "minLength": 1},
+    "identity_boundary": {"type": "string", "minLength": 1},
+    "established_facts": {"type": "array", "items": {"type": "string"}},
+    "decisions": {"type": "array", "items": {"type": "string"}},
+    "rejected_routes": {"type": "array", "items": {"type": "string"}},
+    "authorization_state": {"type": "string", "minLength": 1},
+    "current_checkpoint": {"type": "string", "minLength": 1},
+    "next_action": {"type": "string", "minLength": 1},
+    "completion_definition": {"type": "array", "items": {"type": "string"}, "minItems": 1},
+    "evidence": {"type": "array", "items": {"type": "string"}, "minItems": 1},
+    "updated_at": {"type": "string", "format": "date-time"}
+  },
+  "description": "Stores externalized, verifiable intent and execution state. It must not contain hidden chain-of-thought, credentials, authorization codes, private keys, or secret endpoints."
+}