feat: Implement user authentication and database migration system

- Refactored AuthService to use UserRepository for user authentication.
- Added .env file for environment configuration.
- Created migration system with Migrator and ConnectionFactory classes.
- Added database migration files for creating users table.
- Implemented settings controller for managing database migrations.
- Developed user repository for user data handling.
- Created users controller for user management interface.
- Added frontend standards and migration documentation.
- Introduced reusable UI components and jQuery alerts module.

public/assets/js/modules/jquery-alerts.js

@@ -0,0 +1,72 @@
+"use strict";
+
+(function (factory) {
+  if (typeof module === "object" && module.exports) {
+    module.exports = factory;
+    return;
+  }
+
+  if (typeof window.jQuery !== "undefined") {
+    factory(window.jQuery);
+  }
+})(function ($) {
+  if (!$ || !$.fn) {
+    return;
+  }
+
+  const DEFAULTS = {
+    type: "info",
+    dismissible: true,
+    timeout: 0,
+    classPrefix: "jq-alert",
+  };
+
+  function removeAlert($el) {
+    $el.removeClass("is-visible");
+    window.setTimeout(function () {
+      $el.remove();
+    }, 180);
+  }
+
+  $.fn.orderProAlert = function (options) {
+    const settings = $.extend({}, DEFAULTS, options);
+
+    return this.each(function () {
+      const $host = $(this);
+      const $alert = $("<div>", {
+        class: settings.classPrefix + " " + settings.classPrefix + "--" + settings.type + " is-visible",
+        role: "alert",
+      });
+
+      const $content = $("<div>", {
+        class: settings.classPrefix + "__content",
+        text: String(settings.message || ""),
+      });
+
+      $alert.append($content);
+
+      if (settings.dismissible) {
+        const $close = $("<button>", {
+          class: settings.classPrefix + "__close",
+          type: "button",
+          "aria-label": "Close alert",
+          text: "x",
+        });
+
+        $close.on("click", function () {
+          removeAlert($alert);
+        });
+
+        $alert.append($close);
+      }
+
+      $host.append($alert);
+
+      if (settings.timeout > 0) {
+        window.setTimeout(function () {
+          removeAlert($alert);
+        }, settings.timeout);
+      }
+    });
+  };
+});