Phase 5: Multimethods + Hierarchy system

- types.janet: make-hierarchy, derive*, ancestors, descendants, isa?, underive
- evaluator.janet: defmulti extended with :default and :hierarchy options
  + keyword dispatch-fns wrapped as (fn [x] (get x kw)) for Janet compat
  + hierarchy-based dispatch walks isa? chain when no direct match
- core.janet: real derive, isa?, ancestors, descendants implementations
  replacing stubs; core-remove-method, core-remove-all-methods,
  core-prefer-method added; new core-bindings entries
- 5 test sections (22-26): hierarchy ops, basic dispatch, :default,
  hierarchy dispatch, remove-method — all pass
- 317 tests, 0 failures

.dirge/skills/.usage.json

@@ -1,12 +1,24 @@
 {
+  "jolt-compiler": {
+    "created_by": "agent",
+    "use_count": 6,
+    "view_count": 10,
+    "patch_count": 8,
+    "last_used_at": "2026-06-03T01:15:04.055288+00:00",
+    "last_viewed_at": "2026-06-03T01:15:04.048271+00:00",
+    "last_patched_at": "2026-06-03T01:15:38.021717+00:00",
+    "created_at": "2026-06-02T17:54:38.690279+00:00",
+    "state": "active",
+    "pinned": false
+  },
   "jolt-dev": {
     "created_by": "agent",
-    "use_count": 32,
-    "view_count": 47,
-    "patch_count": 40,
-    "last_used_at": "2026-06-03T00:55:18.036371+00:00",
-    "last_viewed_at": "2026-06-03T00:55:18.017806+00:00",
-    "last_patched_at": "2026-06-03T00:55:51.227868+00:00",
+    "use_count": 33,
+    "view_count": 48,
+    "patch_count": 41,
+    "last_used_at": "2026-06-03T01:13:54.913664+00:00",
+    "last_viewed_at": "2026-06-03T01:13:54.902684+00:00",
+    "last_patched_at": "2026-06-03T01:14:59.915995+00:00",
     "created_at": "2026-06-01T21:26:06.614465+00:00",
     "state": "active",
     "pinned": false
@@ -32,17 +44,5 @@
     "created_at": "2026-06-01T21:49:51.101718+00:00",
     "state": "active",
     "pinned": false
-  },
-  "jolt-compiler": {
-    "created_by": "agent",
-    "use_count": 5,
-    "view_count": 9,
-    "patch_count": 7,
-    "last_used_at": "2026-06-03T00:55:56.946140+00:00",
-    "last_viewed_at": "2026-06-03T00:55:56.935595+00:00",
-    "last_patched_at": "2026-06-03T00:56:15.725835+00:00",
-    "created_at": "2026-06-02T17:54:38.690279+00:00",
-    "state": "active",
-    "pinned": false
   }
 }