Refactor app by modularizing components and extracting utilities.

The changes split large features into smaller, reusable components like `AdminPanel`, `LoginPage`, `TopBar`, `PasswordModal`, and `ChipModal`. Utility functions such as `cycleTag` and `chipStorage` were extracted for better organization. This improves the code's readability, maintainability, and scalability.

frontend/src/components/TopBar.jsx

@@ -0,0 +1,59 @@
+import React from "react";
+import { styles } from "../styles/styles";
+import { stylesTokens } from "../styles/theme";
+
+export default function TopBar({
+  me,
+  userMenuOpen,
+  setUserMenuOpen,
+  openPwModal,
+  doLogout,
+  newGame,
+}) {
+  return (
+    <div style={styles.topBar}>
+      <div>
+        <div style={{ fontWeight: 900, color: stylesTokens.textGold }}>{me.email}</div>
+        <div style={{ fontSize: 12, opacity: 0.8, color: stylesTokens.textDim }}>{me.role}</div>
+      </div>
+
+      <div style={{ display: "flex", gap: 8, alignItems: "center" }} data-user-menu>
+        <div style={{ position: "relative" }}>
+          <button
+            onClick={() => setUserMenuOpen((v) => !v)}
+            style={styles.userBtn}
+            title="User Menü"
+          >
+            <span style={{ fontSize: 16, lineHeight: 1 }}>👤</span>
+            <span>Account</span>
+            <span style={{ opacity: 0.8 }}>▾</span>
+          </button>
+
+          {userMenuOpen && (
+            <div style={styles.userDropdown}>
+              <button onClick={openPwModal} style={styles.userDropdownItem}>
+                Passwort setzen
+              </button>
+
+              <div style={styles.userDropdownDivider} />
+
+              <button
+                onClick={() => {
+                  setUserMenuOpen(false);
+                  doLogout();
+                }}
+                style={{ ...styles.userDropdownItem, color: "#ffb3b3" }}
+              >
+                Logout
+              </button>
+            </div>
+          )}
+        </div>
+
+        <button onClick={newGame} style={styles.primaryBtn}>
+          + Neues Spiel
+        </button>
+      </div>
+    </div>
+  );
+}