Backend: PHP router, CORS config, and API entry point

[Manak-hash]

Description

Build the PHP routing layer that maps HTTP method + path to controllers, handles CORS for the React frontend, and sets up global error handling. This is the backbone of the entire backend.

Tasks

• Create public/index.php as the single entry point (front controller)
• Configure .htaccess in public/ to rewrite all requests to index.php
• Build a minimal router class in helpers/Router.php:
  • Register routes with method + path + controller callback
  • Parse path parameters (e.g. /projects/:id)
  • Return 404 JSON if no route matches
  • Return 405 JSON if method doesn't match
• Register all API routes in routes/api.php
• Add CORS headers for local dev (http://localhost:5173) and handle OPTIONS preflight
• Global exception handler — catch uncaught exceptions and return JSON error
• Set Content-Type: application/json for all responses
• Create helpers/Response.php with success($data, $code) and error($message, $code) helpers
• Test: GET /api/ping returns {"status": "ok"}
• Test: unknown route returns {"error": "Not found"} with 404

Acceptance Criteria

• All API requests go through index.php
• CORS headers allow requests from the React frontend
• Router correctly maps paths including parameters
• Unknown routes return clean JSON 404