Add kernel solid operations and complete Solid3D (create and rigid move)

An additive HostApi::solid_operation builds cadkernel primitives and applies
rigid transforms, verifying each result lifts back losslessly and refusing a
payload it cannot lift. Exposed as doc.solids in Python; Solid3D, Body and
Region are mapped read-only with the opaque payload preserved. The lifecycle
test passes through the real runner with analytic volumes and exact extents as
oracles, DWG and DXF reopen with re-edit, and undo restores exactly.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

plugins/opencad-python/entity_manifest.json

@@ -37,7 +37,10 @@
     "Viewport",
     "ViewBorder",
     "Light",
-    "Ole2Frame"
+    "Ole2Frame",
+    "Solid3D",
+    "Body",
+    "Region"
   ],
   "manual_kinds": [
     "Dimension"
@@ -807,6 +810,87 @@
           "read_only": true
         }
       }
+    },
+    "Solid3D": {
+      "update_only": true,
+      "update_only_message": "Solid3D is built and edited by the geometry kernel: use doc.solids to create solids and move them; a script never writes the ACIS payload",
+      "fields": {
+        "acis_data": {
+          "exclude": true,
+          "_comment": "Opaque ACIS payload; snapshot-readable and never rewritten by a script."
+        },
+        "wires": {
+          "exclude": true,
+          "_comment": "Derived edge wires; regenerated by the host."
+        },
+        "silhouettes": {
+          "exclude": true,
+          "_comment": "Derived; regenerated by the host."
+        },
+        "uid": {
+          "read_only": true
+        },
+        "point_of_reference": {
+          "read_only": true
+        },
+        "history_handle": {
+          "read_only": true
+        }
+      }
+    },
+    "Body": {
+      "update_only": true,
+      "update_only_message": "Body is built and edited by the geometry kernel: use doc.solids to create solids and move them; a script never writes the ACIS payload",
+      "fields": {
+        "acis_data": {
+          "exclude": true,
+          "_comment": "Opaque ACIS payload; snapshot-readable and never rewritten by a script."
+        },
+        "wires": {
+          "exclude": true,
+          "_comment": "Derived edge wires; regenerated by the host."
+        },
+        "silhouettes": {
+          "exclude": true,
+          "_comment": "Derived; regenerated by the host."
+        },
+        "uid": {
+          "read_only": true
+        },
+        "point_of_reference": {
+          "read_only": true
+        },
+        "history_handle": {
+          "read_only": true
+        }
+      }
+    },
+    "Region": {
+      "update_only": true,
+      "update_only_message": "Region is built and edited by the geometry kernel: use doc.solids to create solids and move them; a script never writes the ACIS payload",
+      "fields": {
+        "acis_data": {
+          "exclude": true,
+          "_comment": "Opaque ACIS payload; snapshot-readable and never rewritten by a script."
+        },
+        "wires": {
+          "exclude": true,
+          "_comment": "Derived edge wires; regenerated by the host."
+        },
+        "silhouettes": {
+          "exclude": true,
+          "_comment": "Derived; regenerated by the host."
+        },
+        "uid": {
+          "read_only": true
+        },
+        "point_of_reference": {
+          "read_only": true
+        },
+        "history_handle": {
+          "read_only": true
+        }
+      }
     }
   }
 }