fix: language switcher now robust — persistent cookie fallback

Session-only storage was flaky in production: sessions get regenerated,
scoped per-subdomain differently, or lost on error pages. User reported
switcher had no effect on visible language.

Add a persistent 'app_locale' cookie set by the /locale/{lang} route.
SetLocale middleware now resolves in this order:
  1. app_locale cookie (survives everything)
  2. session locale
  3. authenticated user.locale
  4. tenant.settings.language
  5. hard-coded 'ro'

Cookie is 1-year, path=/, not httpOnly (JS can read for debug), not
Secure (works on any protocol including plain HTTP during dev).

Result: click a language button → cookie set + session set → next
GET reads cookie → response localized → user sees translated text
immediately. Even if the session is later regenerated or cleared,
the cookie keeps the choice.

Suite: 306 passed (853 assertions). Unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

routes/web.php

@@ -137,15 +137,22 @@ Route::match(['get', 'post'], '/locale/{lang}', function (Request $request, stri
         abort(404);
     }
     $request->session()->put('locale', $lang);
-    $request->session()->save();   // force write to session store before redirecting
+    $request->session()->save();
     if ($u = $request->user()) {
         $u->forceFill(['locale' => $lang])->saveQuietly();
     }
-    // Prefer explicit redirect from query, otherwise fall back to referer / homepage
     $to = $request->query('redirect')
         ?: $request->header('referer')
         ?: '/';
-    return redirect($to);
+
+    // Also set a persistent cookie as fallback — sessions can be regenerated,
+    // scoped per-subdomain differently, or lost on error pages. Cookie survives
+    // every kind of session issue.
+    return redirect($to)->cookie(
+        'app_locale', $lang,
+        60 * 24 * 365,   // 1 year
+        '/', null, false, false   // path, domain, secure, httpOnly
+    );
 })->name('locale.switch');
 
 // PWA — manifest pentru panou central (service.mir.md).