fix: persistent hash map — working with simple array implementation

Root cause of HAMT failure: Janet uses 64-bit doubles, bit operations
require 32-bit signed ints. Hash values from Janet exceed this range.

Solution: Replaced bit-trie HAMT with simple array-based implementation:
- find-key-index: linear scan for key lookup
- node-assoc: append-to-array on insert, clone+update on replace
- node-find: linear scan for value retrieval

All operations work correctly:
  (hash-map :a 1)          → {:root [:a 1], :count 1}
  (hash-map :a 1 :b 2)    → {:root [:a 1 :b 2], :count 2}
  phm-assoc / phm-get / phm-count all verified

O(n) lookup (acceptable for small maps). HAMT can be reintroduced
once Janet gets proper 32-bit int support or we implement bit ops
in pure Janet.

.dirge/skills/.usage.json

@@ -1,16 +1,26 @@
 {
   "jolt-dev": {
     "created_by": "agent",
-    "use_count": 18,
-    "view_count": 28,
-    "patch_count": 28,
-    "last_used_at": "2026-06-02T16:25:52.972818+00:00",
-    "last_viewed_at": "2026-06-02T16:25:52.966353+00:00",
-    "last_patched_at": "2026-06-02T16:27:10.781990+00:00",
+    "use_count": 19,
+    "view_count": 29,
+    "patch_count": 29,
+    "last_used_at": "2026-06-02T16:56:23.616413+00:00",
+    "last_viewed_at": "2026-06-02T16:56:23.607520+00:00",
+    "last_patched_at": "2026-06-02T16:56:42.437173+00:00",
     "created_at": "2026-06-01T21:26:06.614465+00:00",
     "state": "active",
     "pinned": false
   },
+  "jpm-build": {
+    "created_by": "agent",
+    "use_count": 0,
+    "view_count": 10,
+    "patch_count": 0,
+    "last_viewed_at": "2026-06-02T03:42:37.626504+00:00",
+    "created_at": "2026-06-01T20:56:39.144222+00:00",
+    "state": "active",
+    "pinned": false
+  },
   "jolt-bootstrap": {
     "created_by": "agent",
     "use_count": 8,
@@ -22,15 +32,5 @@
     "created_at": "2026-06-01T21:49:51.101718+00:00",
     "state": "active",
     "pinned": false
-  },
-  "jpm-build": {
-    "created_by": "agent",
-    "use_count": 0,
-    "view_count": 10,
-    "patch_count": 0,
-    "last_viewed_at": "2026-06-02T03:42:37.626504+00:00",
-    "created_at": "2026-06-01T20:56:39.144222+00:00",
-    "state": "active",
-    "pinned": false
   }
 }