feat: 在设置页新增系统标签管理面板，放开系统标签的 CRUD 限制

- 移除 tags.go 中 UpdateTag 和 DeleteTag 对系统标签的 403 限制
- 在 settings.html 新增「系统标签管理」卡片，支持：
  - 折叠浏览所有系统标签及其选项
  - 编辑标签名称和描述
  - 编辑、添加、删除标签选项
  - 删除整个标签（带二次确认）
- .gitignore 添加 prompt-generator 二进制文件

frontend/settings.html

@@ -49,6 +49,14 @@
             </div>
         </div>
 
+        <!-- 系统标签管理 -->
+        <div class="card mb-4">
+            <div class="card-header">🏷️ 系统标签管理</div>
+            <div class="card-body" id="system-tags-container">
+                <div class="text-sm text-muted" id="system-tags-loading">加载中...</div>
+            </div>
+        </div>
+
         <!-- 账号 -->
         <div class="card mb-4">
             <div class="card-header">🔐 账号</div>
@@ -60,6 +68,11 @@
 
     <script src="/static/common.js"></script>
     <script>
+        function onLogin() {
+            loadSettings();
+            loadSystemTags();
+        }
+
         async function init() {
             const ok = await Auth.check();
             if (!ok) {
@@ -69,6 +82,7 @@
             renderNavbar('settings');
             await loadSettings();
             updateThemeBtn();
+            await loadSystemTags();
         }
 
         async function loadSettings() {
@@ -106,6 +120,111 @@
             document.getElementById('theme-label').textContent = Theme.isDark() ? '🌙 暗色' : '☀️ 亮色';
         }
 
+        // === 系统标签管理 ===
+        let systemTags = [];
+
+        async function loadSystemTags() {
+            const container = document.getElementById('system-tags-container');
+            try {
+                const tags = await API.get('/api/tags');
+                systemTags = (tags || []).filter(t => t.scope === 'system');
+                renderSystemTags();
+            } catch (e) {
+                container.innerHTML = `<div class="text-sm" style="color:var(--danger-color)">加载失败: ${escapeHtml(e.message)}</div>`;
+            }
+        }
+
+        function renderSystemTags() {
+            const container = document.getElementById('system-tags-container');
+            if (!systemTags.length) {
+                container.innerHTML = '<div class="text-sm text-muted">暂无系统标签</div>';
+                return;
+            }
+            container.innerHTML = systemTags.map(tag => `
+                <div class="tag-card" style="border:1px solid var(--border-color);border-radius:8px;margin-bottom:12px;overflow:hidden">
+                    <div class="tag-card-header" style="padding:10px 14px;cursor:pointer;display:flex;align-items:center;justify-content:space-between;background:var(--bg-secondary)"
+                         onclick="this.nextElementSibling.style.display=this.nextElementSibling.style.display==='none'?'block':'none';this.querySelector('.toggle-icon').textContent=this.nextElementSibling.style.display==='none'?'▸':'▾'">
+                        <div style="display:flex;align-items:center;gap:8px">
+                            <span class="toggle-icon" style="font-size:12px;color:var(--text-muted)">▾</span>
+                            <span class="text-sm font-medium">${escapeHtml(tag.name)}</span>
+                            <span class="text-xs text-muted">(${(tag.options||[]).length} 个选项)</span>
+                        </div>
+                        <button class="btn btn-sm btn-danger" onclick="event.stopPropagation();deleteTag(${tag.id},'${escapeHtml(tag.name)}')" title="删除标签">删除</button>
+                    </div>
+                    <div class="tag-card-body" style="padding:14px">
+                        <div style="display:flex;gap:8px;margin-bottom:12px;flex-wrap:wrap">
+                            <input class="input" style="flex:1;min-width:120px" value="${escapeHtml(tag.name)}" placeholder="标签名称" id="tag-name-${tag.id}">
+                            <input class="input" style="flex:2;min-width:180px" value="${escapeHtml(tag.description||'')}" placeholder="标签描述" id="tag-desc-${tag.id}">
+                            <button class="btn btn-primary btn-sm" onclick="updateTag(${tag.id})">保存</button>
+                        </div>
+                        <div id="tag-options-${tag.id}">
+                            ${(tag.options||[]).map(opt => renderOptionRow(tag.id, opt)).join('')}
+                        </div>
+                        <button class="btn btn-sm" style="margin-top:8px" onclick="addOption(${tag.id})">+ 添加选项</button>
+                    </div>
+                </div>
+            `).join('');
+        }
+
+        function renderOptionRow(tagId, opt) {
+            return `
+                <div style="display:flex;gap:8px;margin-bottom:8px;align-items:flex-start" data-opt-id="${opt.id}">
+                    <input class="input" style="flex:1;min-width:100px" value="${escapeHtml(opt.label)}" placeholder="选项名称" id="opt-label-${opt.id}">
+                    <textarea class="input" style="flex:2;min-width:160px;resize:vertical;min-height:36px" placeholder="约束文本" id="opt-text-${opt.id}">${escapeHtml(opt.constraint_text||'')}</textarea>
+                    <button class="btn btn-primary btn-sm" onclick="updateOption(${opt.id},${tagId})" title="保存">✓</button>
+                    <button class="btn btn-sm btn-danger" onclick="deleteOption(${opt.id},${tagId})" title="删除">✕</button>
+                </div>
+            `;
+        }
+
+        async function updateTag(tagId) {
+            const name = document.getElementById(`tag-name-${tagId}`).value.trim();
+            const desc = document.getElementById(`tag-desc-${tagId}`).value.trim();
+            if (!name) { Toast.error('标签名称不能为空'); return; }
+            try {
+                await API.put(`/api/tags/${tagId}`, { name, description: desc });
+                Toast.success('标签已更新');
+                await loadSystemTags();
+            } catch (e) { Toast.error(e.message); }
+        }
+
+        async function deleteTag(tagId, tagName) {
+            if (!confirm(`确定要删除标签「${tagName}」及其所有选项吗？`)) return;
+            try {
+                await API.del(`/api/tags/${tagId}`);
+                Toast.success('标签已删除');
+                await loadSystemTags();
+            } catch (e) { Toast.error(e.message); }
+        }
+
+        async function updateOption(optId, tagId) {
+            const label = document.getElementById(`opt-label-${optId}`).value.trim();
+            const text = document.getElementById(`opt-text-${optId}`).value.trim();
+            if (!label) { Toast.error('选项名称不能为空'); return; }
+            try {
+                await API.put(`/api/tag-options/${optId}`, { label, constraint_text: text });
+                Toast.success('选项已更新');
+                await loadSystemTags();
+            } catch (e) { Toast.error(e.message); }
+        }
+
+        async function deleteOption(optId, tagId) {
+            if (!confirm('确定要删除此选项吗？')) return;
+            try {
+                await API.del(`/api/tag-options/${optId}`);
+                Toast.success('选项已删除');
+                await loadSystemTags();
+            } catch (e) { Toast.error(e.message); }
+        }
+
+        async function addOption(tagId) {
+            try {
+                const res = await API.post(`/api/tags/${tagId}/options`, { label: '新选项', constraint_text: '' });
+                Toast.success('选项已添加');
+                await loadSystemTags();
+            } catch (e) { Toast.error(e.message); }
+        }
+
         init();
     </script>
 </body>