Implement FarmQ Admin machine name display fix for Magic DNS

Fix machine management page to display proper Magic DNS names:
- Use given_name instead of hostname for machine display
- Add Magic DNS address with copy-to-clipboard functionality
- Distinguish between machine name and OS hostname like Headplane
- Enhance UI with Magic DNS information (.headscale.local)

Changes:
- farmq-admin/utils/database_new.py: Use given_name for machine_name
- farmq-admin/models/farmq_models.py: Update sync logic for given_name
- farmq-admin/templates/machines/list.html: Add Magic DNS display with copy feature
- FARMQ_ADMIN_MACHINE_NAME_FIX_PLAN.md: Complete analysis and implementation plan

Now displays:
- Machine Name: pbs-hp (Magic DNS name)
- Magic DNS: pbs-hp.headscale.local (with copy button)
- OS Hostname: proxmox-backup-server (system name)

🤖 Generated with [Claude Code](https://claude.ai/code)

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

farmq-admin/templates/machines/list.html

@@ -113,7 +113,17 @@
                                             </div>
                                             <div>
                                                 <strong>{{ machine_data.machine_name or machine_data.hostname }}</strong>
-                                                <div class="small text-muted">{{ machine_data.hostname }}</div>
+                                                <div class="small text-success">
+                                                    <i class="fas fa-link"></i> <code>{{ machine_data.machine_name or machine_data.hostname }}.headscale.local</code>
+                                                    <button class="btn btn-sm btn-outline-secondary ms-1" onclick="copyToClipboard('{{ machine_data.machine_name or machine_data.hostname }}.headscale.local')" title="Magic DNS 주소 복사">
+                                                        <i class="fas fa-copy"></i>
+                                                    </button>
+                                                </div>
+                                                {% if machine_data.hostname != (machine_data.machine_name or machine_data.hostname) %}
+                                                <div class="small text-muted">
+                                                    <i class="fas fa-server"></i> OS: {{ machine_data.hostname }}
+                                                </div>
+                                                {% endif %}
                                                 <div class="small">
                                                     <i class="fas fa-user"></i> {{ machine_data.headscale_user_name or '미지정' }}
                                                 </div>
@@ -440,6 +450,16 @@ function deleteNode(nodeId, nodeName) {
     });
 }
 
+// Magic DNS 주소 클립보드 복사 기능
+function copyToClipboard(text) {
+    navigator.clipboard.writeText(text).then(() => {
+        showToast(`Magic DNS 주소가 복사되었습니다: ${text}`, 'success');
+    }).catch(err => {
+        console.error('복사 실패:', err);
+        showToast('복사에 실패했습니다.', 'danger');
+    });
+}
+
 // 초기 카운터 설정
 document.addEventListener('DOMContentLoaded', function() {
     filterMachines();