feat(api): canon log JSON Schema + validator, enforce §7 luck boundary

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/tests/test_canon_log_schema.py

@@ -0,0 +1,58 @@
+import copy
+import json
+from pathlib import Path
+
+from app.canon_log import validate_canon_log
+
+FIXTURE = Path(__file__).parent / "fixtures" / "canon_log_valid.json"
+
+
+def _valid():
+    with open(FIXTURE) as f:
+        return json.load(f)
+
+
+def test_valid_canon_log_passes():
+    assert validate_canon_log(_valid()) == []
+
+
+def test_numeric_luck_is_rejected():
+    # Charter §7: the AI must never be able to calculate Luck. A stray numeric
+    # luck field must fail validation, not slip through.
+    doc = _valid()
+    doc["player"]["luck"] = 5
+    assert validate_canon_log(doc) != []
+
+
+def test_recent_events_over_five_is_rejected():
+    doc = _valid()
+    doc["recent_events"] = [f"event {i}" for i in range(6)]
+    assert validate_canon_log(doc) != []
+
+
+def test_disposition_out_of_range_is_rejected():
+    doc = _valid()
+    doc["party"][0]["disposition"] = 200
+    assert validate_canon_log(doc) != []
+
+
+def test_unknown_quest_status_is_rejected():
+    doc = _valid()
+    doc["active_quests"][0]["status"] = "abandoned"
+    assert validate_canon_log(doc) != []
+
+
+def test_humiliation_weight_bounds_enforced():
+    doc = _valid()
+    doc["humiliations"][0]["weight"] = 11
+    assert validate_canon_log(doc) != []
+
+
+def test_empty_optional_arrays_are_allowed():
+    doc = _valid()
+    doc["party"] = []
+    doc["recent_events"] = []
+    doc["established_facts"] = []
+    doc["active_quests"] = []
+    doc["humiliations"] = []
+    assert validate_canon_log(doc) == []