fix: language switcher works — GET route, simple links, forced RO fallback

The previous POST-based switcher failed silently: CSRF token check
returned 419 when clicking, and the session never persisted.

Root causes:
- POST requires @csrf token, but the test path fetched pages that had
  no matching form so the token in the DOM didn't match the session
- Some tenant subdomains had SESSION_DOMAIN scoped differently, so
  the cookie set by POST didn't come back on the follow-up GET
- Prod .env had APP_LOCALE=en which took precedence over the config
  edit; when session had no locale yet, defaulted to English

Fixes:

1. Route accepts BOTH GET and POST via Route::match(['get', 'post']).
   Setting your own language is not a security concern — GET is fine.

2. Route explicitly calls $request->session()->save() before redirect,
   forcing the session store to write before the redirect fires.
   Also honors ?redirect=<url> query so the user lands back on their
   original page rather than referer-guessing.

3. lang-switcher partial rewrites to plain <a href> tags (no @csrf,
   no forms). Each link points at /locale/{code}?redirect={current-url}
   so the switch happens in a single hop with predictable target.

4. SetLocale middleware hard-codes 'ro' as the ultimate fallback,
   ignoring config/env. The Romanian portal is the default
   client-facing surface; if a client has no session locale set and
   no user account, they see Romanian (safer than English which has
   no portal translations).

Suite: 306 passed (853 assertions). Unchanged.

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

routes/web.php

@@ -129,16 +129,23 @@ Route::post('/t/{token}/approve/{kind}/{lineToken}', [\App\Http\Controllers\Trac
     ->where('lineToken', '[A-Za-z0-9]{16,32}')
     ->name('tracking.approve');
 
-// Locale switch — POST /locale/{lang} sets session and persists to user.
-Route::post('/locale/{lang}', function (Request $request, string $lang) {
+// Locale switch — GET/POST /locale/{lang} sets session and persists to user.
+// GET intentionally supported so simple <a> links (no CSRF token) work; anyone
+// setting their own language is not a security concern.
+Route::match(['get', 'post'], '/locale/{lang}', function (Request $request, string $lang) {
     if (! in_array($lang, ['ro', 'ru', 'en'], true)) {
         abort(404);
     }
     $request->session()->put('locale', $lang);
+    $request->session()->save();   // force write to session store before redirecting
     if ($u = $request->user()) {
         $u->forceFill(['locale' => $lang])->saveQuietly();
     }
-    return back();
+    // Prefer explicit redirect from query, otherwise fall back to referer / homepage
+    $to = $request->query('redirect')
+        ?: $request->header('referer')
+        ?: '/';
+    return redirect($to);
 })->name('locale.switch');
 
 // PWA — manifest pentru panou central (service.mir.md).