feat(myTischtennis): implement session restoration for browser automation login

- Enhanced the loginWithBrowserAutomation method to accept an options parameter for restoring a saved Playwright session, allowing users to bypass CAPTCHA if the session is still valid.
- Added a new playwrightStorageState field in the MyTischtennis model to store the encrypted browser storage state, facilitating session persistence.
- Updated myTischtennisService to utilize the saved storage state during login attempts, improving user experience by reducing unnecessary CAPTCHA challenges.

backend/clients/myTischtennisClient.js

@@ -352,11 +352,62 @@ class MyTischtennisClient {
    * Browser-based fallback login for CAPTCHA flows.
    * @param {string} email
    * @param {string} password
-   * @returns {Promise<Object>} Login response with token and session data
+   * @param {Object} [options]
+   * @param {Object} [options.savedStorageState] - Playwright storage state from a previous session.
+   *   If provided and the stored auth cookie is still valid, returns immediately without a new login.
+   * @returns {Promise<Object>} Login response with token, session data, and `storageState` for persistence.
    */
-  async loginWithBrowserAutomation(email, password) {
+  async loginWithBrowserAutomation(email, password, options = {}) {
+    const { savedStorageState } = options;
     let browser = null;
     let context = null;
+
+    // --- Fast path: restore a saved Playwright session ---
+    if (savedStorageState) {
+      try {
+        browser = await chromium.launch({ headless: true, args: ['--no-sandbox', '--disable-dev-shm-usage'] });
+        context = await browser.newContext({ storageState: savedStorageState });
+        const cookies = await context.cookies('https://www.mytischtennis.de');
+        const authCookie = cookies.find((c) => c.name === 'sb-10-auth-token' || /^sb-\d+-auth-token$/.test(c.name));
+        if (authCookie?.value) {
+          const tokenMatch = String(authCookie.value).match(/^base64-(.+)$/);
+          if (tokenMatch) {
+            const tokenData = JSON.parse(Buffer.from(tokenMatch[1], 'base64').toString('utf-8'));
+            const nowSec = Math.floor(Date.now() / 1000);
+            // Accept if not expired (with 5-minute safety buffer)
+            if (tokenData.expires_at && tokenData.expires_at > nowSec + 300) {
+              console.log('[myTischtennisClient.playwright] Restored session from saved state (no CAPTCHA needed)');
+              const storageState = await context.storageState();
+              await context.close();
+              await browser.close();
+              browser = null; context = null;
+              return {
+                success: true,
+                accessToken: tokenData.access_token,
+                refreshToken: tokenData.refresh_token,
+                expiresAt: tokenData.expires_at,
+                expiresIn: tokenData.expires_in,
+                user: tokenData.user,
+                cookie: `sb-10-auth-token=${authCookie.value}`,
+                storageState,
+                restoredFromCache: true
+              };
+            }
+          }
+        }
+        // Cookie absent or expired → close and fall through to full login
+        console.log('[myTischtennisClient.playwright] Saved session expired or invalid, starting full login');
+        await context.close();
+        await browser.close();
+        browser = null; context = null;
+      } catch (restoreErr) {
+        console.warn('[myTischtennisClient.playwright] Session restore failed, starting full login:', restoreErr.message);
+        try { if (context) await context.close(); } catch (_e) { /* ignore */ }
+        try { if (browser) await browser.close(); } catch (_e) { /* ignore */ }
+        browser = null; context = null;
+      }
+    }
+
     try {
       console.log('[myTischtennisClient.playwright] Start browser login flow');
       browser = await chromium.launch({
@@ -686,6 +737,11 @@ class MyTischtennisClient {
       }
 
       const cookie = `sb-10-auth-token=${authCookieObj.value}`;
+
+      // Persist the full browser storage state so future calls can skip the CAPTCHA flow.
+      let storageState = null;
+      try { storageState = await context.storageState(); } catch (_e) { /* ignore */ }
+
       console.log('[myTischtennisClient.playwright] Browser login successful');
       return {
         success: true,
@@ -694,7 +750,8 @@ class MyTischtennisClient {
         expiresAt: tokenData.expires_at,
         expiresIn: tokenData.expires_in,
         user: tokenData.user,
-        cookie
+        cookie,
+        storageState
       };
     } catch (error) {
       const rawMessage = String(error?.message || error || 'Playwright-Login fehlgeschlagen');