fix: renew_cert regenerates Caddyfile before reload

A stale or empty-token Caddyfile on disk caused Caddy to reject the
/load request, so the Renew button appeared to do nothing. Now
renew_cert() calls regenerate_with_installed([]) first, which writes a
fresh Caddyfile from current identity/config before reloading Caddy.
This ensures a broken on-disk file never blocks ACME renewal.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_caddy_manager.py

@@ -493,17 +493,17 @@ class TestRenewCert(unittest.TestCase):
         self.assertFalse(result['ok'])
         self.assertIn('LAN', result['error'])
 
-    def test_acme_mode_calls_reload(self):
+    def test_acme_mode_calls_regenerate(self):
         mgr = _mgr(identity={'domain_mode': 'pic_ngo'})
-        with patch.object(mgr, 'reload_caddy', return_value=True) as mock_reload:
+        with patch.object(mgr, 'regenerate_with_installed', return_value=True) as mock_regen:
             result = mgr.renew_cert()
-        mock_reload.assert_called_once()
+        mock_regen.assert_called_once_with([])
         self.assertTrue(result['ok'])
         self.assertEqual(result['status'], 'pending')
 
     def test_reload_failure_propagated(self):
         mgr = _mgr(identity={'domain_mode': 'cloudflare'})
-        with patch.object(mgr, 'reload_caddy', return_value=False):
+        with patch.object(mgr, 'regenerate_with_installed', return_value=False):
             result = mgr.renew_cert()
         self.assertFalse(result['ok'])
         self.assertIn('reload failed', result['error'])
@@ -512,7 +512,7 @@ class TestRenewCert(unittest.TestCase):
         import time
         mgr = _mgr(identity={'domain_mode': 'pic_ngo'})
         mgr._cert_refreshed_at = time.monotonic()
-        with patch.object(mgr, 'reload_caddy', return_value=True):
+        with patch.object(mgr, 'regenerate_with_installed', return_value=True):
             mgr.renew_cert()
         self.assertIsNone(mgr._cert_refreshed_at)