feat: domains, transports, logs, quarantine, spam filter, i18n + UX fixes

Features added:
- Admin > Domains: add domains to Mailcow servers, auto-generate DKIM,
  display full DNS record set (MX, SPF, DMARC, DKIM, autoconfig CNAMEs)
  with one-click copy per record
- Admin > Transports: manage sender-dependent relay hosts (add/delete)
- Admin > Logs: view Postfix, Dovecot, Rspamd, Ratelimit, API and other
  server logs in a dark scrollable panel
- My Account: per-domain Quarantine panel — view score, sender, subject,
  date; permanently delete quarantined messages
- My Account: per-mailbox Spam Filter slider (1–15 threshold) saved via API
- My Account: Aliases & Forwarders (alias creation doubles as forwarder
  to any external address)

UX fixes:
- Quota 0 now displays ∞ (unlimited) in both admin and account views
- Admin mailbox action buttons replaced with Dashicon icon buttons
  (lock, chart-bar, trash) with title tooltips

i18n:
- load_plugin_textdomain registered on init hook
- All user-facing PHP strings wrapped in __() / esc_html__()
- Translated strings array passed to account JS via wp_localize_script
- woocow-es_ES.po/.mo — Spanish translation
- woocow-ro_RO.po/.mo — Romanian translation (with correct plural forms)
- English remains the fallback

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

includes/class-woocow-api.php

@@ -18,7 +18,7 @@ class WooCow_API {
 
     // ── Core HTTP ────────────────────────────────────────────────────────────
 
-    private function request( string $method, string $endpoint, array $body = [] ): array {
+    public function request( string $method, string $endpoint, array $body = [] ): array {
         $args = [
             'method'    => strtoupper( $method ),
             'timeout'   => $this->timeout,
@@ -145,6 +145,44 @@ class WooCow_API {
         return $this->request( 'POST', '/api/v1/delete/domain-admin', [ 'items' => [ $username ] ] );
     }
 
+    // ── DKIM ─────────────────────────────────────────────────────────────────
+
+    public function get_dkim( string $domain ): array {
+        return $this->request( 'GET', '/api/v1/get/dkim/' . rawurlencode( $domain ) );
+    }
+
+    public function generate_dkim( string $domain, string $selector = 'dkim', int $key_size = 2048 ): array {
+        return $this->request( 'POST', '/api/v1/add/dkim', [
+            'domains'       => $domain,
+            'dkim_selector' => $selector,
+            'key_size'      => $key_size,
+        ] );
+    }
+
+    // ── Relayhosts ───────────────────────────────────────────────────────────
+
+    public function get_relayhosts(): array {
+        return $this->request( 'GET', '/api/v1/get/relayhost/all' );
+    }
+
+    public function create_relayhost( array $data ): array {
+        return $this->request( 'POST', '/api/v1/add/relayhost', $data );
+    }
+
+    public function delete_relayhost( int $id ): array {
+        return $this->request( 'POST', '/api/v1/delete/relayhost', [ 'items' => [ $id ] ] );
+    }
+
+    // ── Quarantine ───────────────────────────────────────────────────────────
+
+    public function get_quarantine(): array {
+        return $this->request( 'GET', '/api/v1/get/quarantine/all' );
+    }
+
+    public function delete_quarantine( int $id ): array {
+        return $this->request( 'POST', '/api/v1/delete/quarantine', [ 'items' => [ $id ] ] );
+    }
+
     // ── Helpers ──────────────────────────────────────────────────────────────
 
     public function get_webmail_url(): string {