Add MariaDB integration and repositories

Introduce DB support and repos: add modules/database.js (connection pool + runDDL) and SQL DDL files (data/ddl/*) for servers, users, providers, identities and credentials. Add repository layers: users, servers, providers, identities, credentials. Update server.js to run DDL at startup. Update .env.example with DB settings and bump dependencies in package.json/package-lock.json (add mariadb, bump dotenv/helmet/path-to-regexp/zod and dev tool upgrades). Error handling and logging included for DDL and repo operations.

.env.example

@@ -1,2 +1,9 @@
-WEB_PORT=3000
-IS_PROD=FALSE
+#Config
+WEB_PORT=8877
+IS_PROD=FALSE
+
+#MariaDB
+DATABASE_HOST="host"
+DATABASE_USER="changeme"
+DATABASE_PASSWORD="password"
+DATABASE_NAME="tcjourney"