feat(blocks): block_define — typed primitives + ATTDEFs on both engines

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

docs/tool-inventory.json

@@ -3,7 +3,7 @@
   "schema_version": 1,
   "package_version": "1.5.1",
   "totals": {
-    "tools": 154,
+    "tools": 155,
     "resources": 6,
     "prompts": 5,
     "groups": 19
@@ -11,7 +11,7 @@
   "groups": {
     "analysis": 12,
     "batch": 3,
-    "blocks": 8,
+    "blocks": 9,
     "corner_ops": 4,
     "dimensions": 5,
     "drawing": 11,
@@ -187,6 +187,20 @@
         "readOnlyHint": false
       }
     },
+    {
+      "name": "block_define",
+      "group": "blocks",
+      "cost": "mutate",
+      "summary": "Define a block from typed primitives and attribute definitions, on both engines.",
+      "tags": [
+        "block",
+        "create"
+      ],
+      "annotations": {
+        "title": "Define Block",
+        "readOnlyHint": false
+      }
+    },
     {
       "name": "block_explode",
       "group": "blocks",