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/scripts/test_compile_emergent_skills.py

@@ -0,0 +1,48 @@
+import json
+import tempfile
+import unittest
+from pathlib import Path
+
+from compile_emergent_skills import compile_candidates, load_receipts
+
+
+class EmergentSkillCompilerTests(unittest.TestCase):
+    def test_repository_receipts_compile_as_candidates_only(self):
+        result = compile_candidates(load_receipts())
+        self.assertGreaterEqual(result["source_receipt_count"], 4)
+        self.assertTrue(result["candidates"])
+        for candidate in result["candidates"]:
+            self.assertEqual(candidate["enforcement_level"], "CANDIDATE_ONLY")
+            self.assertFalse(candidate["hard_block_allowed"])
+
+    def test_conflicting_invariant_text_is_rejected(self):
+        receipt = {
+            "schema": "guanghu.ops-experience-receipt/v1",
+            "receipt_id": "A",
+            "intent": "i",
+            "scope": "s",
+            "input": "i",
+            "evidence": ["e"],
+            "decision": "d",
+            "action": "a",
+            "observed_result": "r",
+            "correction": "c",
+            "invariant_id": "INV-X",
+            "invariant": "one",
+            "verification": ["v"],
+            "receipt_path": "p",
+            "promotion_state": "CANDIDATE_ONLY",
+            "recorded_at": "2026-07-26T00:00:00Z",
+        }
+        with self.assertRaises(ValueError):
+            compile_candidates([receipt, {**receipt, "receipt_id": "B", "invariant": "two"}])
+
+    def test_missing_fields_fail_closed(self):
+        with tempfile.TemporaryDirectory() as directory:
+            Path(directory, "bad.json").write_text(json.dumps({"schema": "guanghu.ops-experience-receipt/v1"}))
+            with self.assertRaises(ValueError):
+                load_receipts(Path(directory))
+
+
+if __name__ == "__main__":
+    unittest.main()