Remove custom API endpoints in favor of Payload's native REST API

- Removed custom endpoint handler and endpoints directory
- Removed enableApi configuration option from plugin
- Updated client hooks to use Payload's native collection API
- Updated documentation to reflect API changes
- Updated view component to handle Payload API response format

The plugin now uses Payload CMS's built-in REST API for the feature-flags collection, which provides standard query syntax, pagination, and automatic access control enforcement.

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

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@xtr-dev/payload-feature-flags",
-  "version": "0.0.7",
+  "version": "0.0.9",
   "description": "Feature flags plugin for Payload CMS - manage feature toggles, A/B tests, and gradual rollouts",
   "license": "MIT",
   "type": "module",