Update README.md and add debug error handlers

- Completely rewrote README with all new features and admin routes
- Cleaned up remaining migration files
- Added detailed PHP error/exception handlers to dependencies API
  to help debug the 500 error

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

api/ticket_dependencies.php

@@ -7,10 +7,36 @@
  * DELETE: Remove a dependency
  */
 
-// Capture errors for debugging
+// Capture ALL errors for debugging
 ini_set('display_errors', 0);
 error_reporting(E_ALL);
 
+// Custom error handler to return JSON errors
+set_error_handler(function($errno, $errstr, $errfile, $errline) {
+    http_response_code(500);
+    header('Content-Type: application/json');
+    echo json_encode([
+        'success' => false,
+        'error' => "PHP Error: $errstr",
+        'file' => basename($errfile),
+        'line' => $errline
+    ]);
+    exit;
+});
+
+// Custom exception handler
+set_exception_handler(function($e) {
+    http_response_code(500);
+    header('Content-Type: application/json');
+    echo json_encode([
+        'success' => false,
+        'error' => 'Exception: ' . $e->getMessage(),
+        'file' => basename($e->getFile()),
+        'line' => $e->getLine()
+    ]);
+    exit;
+});
+
 // Apply rate limiting (also starts session)
 require_once dirname(__DIR__) . '/middleware/RateLimitMiddleware.php';
 RateLimitMiddleware::apply('api');