feat: 补全收藏与分类功能

- 后台编辑区新增★收藏切换按钮(即时生效)
- 后台侧栏新增快速筛选: 全部/★收藏/分类
- 前台快速筛选新增分类chips(按分类过滤)
- 两种模式均含暗色样式适配

web/index.html

@@ -72,6 +72,9 @@
         body.dark .filter-item:hover { background: #1e232d; }
         body.dark .filter-item.active { background: #1b2a44; color: #7aa2f7; }
         body.dark .filter-item.active svg { fill: #7aa2f7; }
+        body.dark .filter-chip { background: #1a1e26; border-color: #2a3040; color: #c9ced8; }
+        body.dark .filter-chip:hover { background: #2a3040; }
+        body.dark .filter-chip.active { background: #1976d2; color: #fff; border-color: #1976d2; }
 
         body.dark .note-list { border-top: 1px solid #232733; }
         body.dark .note-item:hover { background: #1e232d; }
@@ -285,6 +288,21 @@
         .filter-item:hover { background: #f1f3f4; }
         .filter-item.active { background: #e3f2fd; color: #1976d2; }
         .filter-item svg { width: 16px; height: 16px; }
+
+        /* 分类筛选 chips */
+        .filter-chip {
+            padding: 4px 11px;
+            border: 1px solid #e0e0e0;
+            border-radius: 14px;
+            background: #fff;
+            color: #555;
+            font-size: 12px;
+            cursor: pointer;
+            white-space: nowrap;
+            transition: all 0.2s;
+        }
+        .filter-chip:hover { background: #f1f3f4; }
+        .filter-chip.active { background: #1976d2; color: #fff; border-color: #1976d2; }
         
         .note-list {
             border-top: 1px solid #e0e0e0;
@@ -631,6 +649,7 @@
                     <svg viewBox="0 0 24 24"><path d="M12 21.35l-1.45-1.32C5.4 15.36 2 12.28 2 8.5 2 5.42 4.42 3 7.5 3c1.74 0 3.41.81 4.5 2.09C13.09 3.81 14.76 3 16.5 3 19.58 3 22 5.42 22 8.5c0 3.78-3.4 6.86-8.55 11.54L12 21.35z"/></svg>
                     收藏笔记
                 </div>
+                <div class="cat-filters" id="catFilters" style="padding: 4px 16px 6px; display: flex; flex-wrap: wrap; gap: 6px;"></div>
             </div>
         </div>
 
@@ -677,6 +696,52 @@
 
         async function init() {
             await loadTree();
+            await loadCategories();
+        }
+
+        // 加载分类并在筛选区渲染 chips
+        async function loadCategories() {
+            try {
+                const res = await fetch(`${API}/categories`);
+                const data = await res.json();
+                const cats = data.data || [];
+                const box = document.getElementById('catFilters');
+                if (!box) return;
+                if (cats.length === 0) {
+                    box.innerHTML = '';
+                    return;
+                }
+                box.innerHTML = cats.map(cat => 
+                    `<span class="filter-chip ${currentFilter.type === 'category' && currentFilter.value === cat ? 'active' : ''}" onclick="filterCategory('${escapeHtml(cat)}')">${escapeHtml(cat)}</span>`
+                ).join('');
+            } catch (e) { /* 忽略 */ }
+        }
+
+        // 按分类筛选
+        async function filterCategory(cat) {
+            currentFilter = { type: 'category', value: cat };
+            updateFilterUI();
+            renderCatFilters();
+            try {
+                const res = await fetch(`${API}/notes?category=${encodeURIComponent(cat)}&page_size=100`);
+                const data = await res.json();
+                if (data.code === 0) {
+                    flatNotes = data.data || [];
+                    renderFlatNotes();
+                }
+            } catch (err) {
+                showToast('加载失败', 'error');
+            }
+        }
+
+        function renderCatFilters() {
+            const box = document.getElementById('catFilters');
+            if (!box) return;
+            const chips = box.querySelectorAll('.filter-chip');
+            chips.forEach(chip => {
+                chip.classList.toggle('active',
+                    currentFilter.type === 'category' && chip.textContent === currentFilter.value);
+            });
         }
 
         async function loadTree() {
@@ -895,12 +960,14 @@
         async function filterAll() {
             currentFilter = { type: 'all' };
             updateFilterUI();
+            renderCatFilters();
             await loadTree();
         }
 
         async function filterFavorites() {
             currentFilter = { type: 'favorites' };
             updateFilterUI();
+            renderCatFilters();
             try {
                 const res = await fetch(`${API}/notes?favorite=true&page_size=100`);
                 const data = await res.json();