Fix deployment: remove stale 'core' team references and add validation

PR #17 removed the 'core' group but left references in repoAccess.ts,
causing deployments to fail since Nov 25th.

Changes:
- Remove 'core' team references from 6 repositories in repoAccess.ts
- Replace with 'core-maintainers' to maintain equivalent permissions
- Add scripts/validate-config.ts to validate all team references
- Add pre-commit hook to run validation on config changes
- Add npm run validate script

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package.json

@@ -4,7 +4,8 @@
   "description": "Infrastructure as Code for MCP access management",
   "main": "src/index.ts",
   "scripts": {
-    "build": "tsc"
+    "build": "tsc",
+    "validate": "npx ts-node scripts/validate-config.ts"
   },
   "license": "MIT",
   "dependencies": {