feat(tkqc): 관리함 이슈 프로젝트 변경 + cause_person 필드명 버그 수정

- 모바일/데스크톱 관리함에서 이슈 소속 프로젝트 변경 가능
- 프로젝트 변경 시 sequence_no 자동 재계산 (DB 함수 사용)
- in_progress 상태에서만 변경 허용 (프론트+백엔드 이중 제한)
- cause_person → responsible_person_detail 필드명 불일치 수정

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

system3-nonconformance/web/static/js/pages/issues-management.js

@@ -66,6 +66,7 @@ async function loadProjects() {
 
         if (response.ok) {
             projects = await response.json();
+            window._cachedProjects = projects;
             updateProjectFilter();
         }
     } catch (error) {
@@ -1573,7 +1574,10 @@ function openIssueEditModal(issueId, isCompletionMode = false) {
                                 <div class="space-y-3">
                                     <div>
                                         <label class="block text-sm font-medium text-gray-700 mb-1">프로젝트</label>
-                                        <input type="text" value="${project ? project.project_name : '-'}" class="w-full px-3 py-2 bg-gray-100 border border-gray-300 rounded-lg text-sm" readonly>
+                                        <select id="edit-issue-project-${issue.id}" class="w-full px-3 py-2 border border-gray-300 rounded-lg text-sm focus:ring-2 focus:ring-blue-500"${issue.review_status === 'completed' ? ' disabled' : ''}>
+                                            <option value="">선택하세요</option>
+                                            ${(window._cachedProjects || []).map(p => `<option value="${p.id}"${p.id == issue.project_id ? ' selected' : ''}>${p.project_name || p.job_no}</option>`).join('')}
+                                        </select>
                                     </div>
                                     <div>
                                         <label class="block text-sm font-medium text-gray-700 mb-1">부적합명</label>
@@ -1845,6 +1849,27 @@ async function saveIssueFromModal(issueId) {
 
     const combinedDescription = title + (detail ? '\n' + detail : '');
 
+    // 프로젝트 변경 처리
+    const projectSelect = document.getElementById(`edit-issue-project-${issueId}`);
+    if (projectSelect) {
+        const newProjectId = parseInt(projectSelect.value);
+        const issue = issues.find(i => i.id === issueId);
+        if (newProjectId && issue && newProjectId !== issue.project_id) {
+            try {
+                const projResp = await fetch(`/api/issues/${issueId}`, {
+                    method: 'PUT',
+                    headers: { 'Authorization': `Bearer ${TokenManager.getToken()}`, 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ project_id: newProjectId })
+                });
+                if (!projResp.ok) {
+                    const err = await projResp.json();
+                    showToast(err.detail || '프로젝트 변경 실패', 'error');
+                    return;
+                }
+            } catch (e) { showToast('프로젝트 변경 실패: ' + e.message, 'error'); return; }
+        }
+    }
+
     const requestBody = {
         final_description: combinedDescription,
         final_category: category,