Fix ESM import error for @xenova/transformers

Change static import to dynamic import() for @xenova/transformers
which is an ESM-only package. This fixes ERR_REQUIRE_ESM when
running via npx in CommonJS environments.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@colbymchenry/codegraph",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "A local-first code intelligence system that builds a semantic knowledge graph from any codebase",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",