Add badges, checkins, and transport endpoints

Introduce gamification and check-in support plus expanded transport/admin APIs. Added DDL for checkins, badges and user_badges. New repositories: badgeRepository, userBadgeRepository, checkinRepository. New routes: admin badge management, admin transport (lines/platforms/stations), public transport endpoints, user checkins and stations endpoints, and user badges on /me. Services updated: adminService (badge CRUD & user assignment), userService (checkins, badge queries), authService (hasAdminRights). Minor package.json name update. These changes implement database, repo, service and route wiring for badges, user_badins and checkin features and additional transport admin routes.

data/ddl/14_badges.sql

@@ -0,0 +1,10 @@
+CREATE TABLE IF NOT EXISTS `badges` (
+    `id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
+    `name` VARCHAR(255) NOT NULL UNIQUE,
+    `description` TEXT,
+    `icon` TEXT,
+    `condition` VARCHAR(255) NOT NULL COMMENT 'Ex: checkins_count >= 10',
+    `createdAt` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    PRIMARY KEY (id)
+);