fix: Use bare codegraph everywhere, add preuninstall cleanup

- Revert configs (MCP, hooks) to use bare `codegraph` command
- Remove all npx references from configs and messaging
- Add preuninstall script that runs on `npm uninstall -g` to clean up
  MCP server, permissions, hooks, and CLAUDE.md section
- Show uninstall instructions in post-install next steps

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@colbymchenry/codegraph",
-  "version": "0.5.5",
+  "version": "0.6.0",
   "description": "Supercharge Claude Code with semantic code intelligence. 30% fewer tokens, 25% fewer tool calls, 100% local.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -15,6 +15,7 @@
   "scripts": {
     "build": "tsc && npm run copy-assets",
     "postinstall": "node scripts/postinstall.js",
+    "preuninstall": "node dist/bin/uninstall.js",
     "copy-assets": "node -e \"const fs=require('fs');fs.mkdirSync('dist/db',{recursive:true});fs.copyFileSync('src/db/schema.sql','dist/db/schema.sql');fs.mkdirSync('dist/extraction/wasm',{recursive:true});fs.readdirSync('src/extraction/wasm').filter(f=>f.endsWith('.wasm')).forEach(f=>fs.copyFileSync('src/extraction/wasm/'+f,'dist/extraction/wasm/'+f))\"",
     "dev": "tsc --watch",
     "cli": "npm run build && node dist/bin/codegraph.js",