Include README.md in npm package

- Add README.md to files array so it appears on npmjs.com
- Bump version to 0.2.8

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@colbymchenry/codegraph",
-  "version": "0.2.7",
+  "version": "0.2.8",
   "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",
@@ -8,7 +8,8 @@
     "codegraph": "./dist/bin/codegraph.js"
   },
   "files": [
-    "dist"
+    "dist",
+    "README.md"
   ],
   "scripts": {
     "build": "tsc && npm run copy-assets",