Initial commit: Flutter app + PHP/MySQL backend on Hostinger

Replaces Firebase with a self-hosted PHP/MySQL API served from
winded.prymsolutions.com. Includes full backend (schema, auth, events,
teams, brackets, suggestions, stats, media, file upload) and updated
Flutter repositories and domain models.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/api/events/register.php

@@ -0,0 +1,40 @@
+<?php
+require_once __DIR__ . '/../config/helpers.php';
+cors();
+
+$payload  = require_auth();
+$uid      = $payload['uid'];
+$event_id = $_GET['event_id'] ?? (body()['event_id'] ?? '');
+$method   = $_SERVER['REQUEST_METHOD'];
+
+if ($event_id === '') json_err('Missing event_id');
+
+$db = db();
+
+if ($method === 'POST') {
+    try {
+        $db->prepare(
+            'INSERT INTO event_registrations (id, event_id, user_id) VALUES (?, ?, ?)'
+        )->execute([uuid(), $event_id, $uid]);
+    } catch (PDOException $e) {
+        // Unique constraint: already registered — treat as success
+    }
+    json_ok(['registered' => true]);
+}
+
+if ($method === 'DELETE') {
+    $db->prepare(
+        'DELETE FROM event_registrations WHERE event_id = ? AND user_id = ?'
+    )->execute([$event_id, $uid]);
+    json_ok(['unregistered' => true]);
+}
+
+if ($method === 'GET') {
+    $stmt = $db->prepare(
+        'SELECT * FROM event_registrations WHERE event_id = ? AND user_id = ?'
+    );
+    $stmt->execute([$event_id, $uid]);
+    json_ok(['registered' => (bool)$stmt->fetch()]);
+}
+
+json_err('Method not allowed', 405);