feat: 实现全局响应式布局，适配不同设备、不同屏幕、不同分辨率

- 统一断点体系：560px(手机)、900px(平板)、1180px(小桌面)
- Shell导航：900px底部导航条、560px紧凑布局、顶栏触控优化
- 电商页面：三栏布局在平板/手机下改为单栏堆叠+横向标签切换
- 工作台：启动页编辑器全宽、消息气泡适配窄屏、建议标签换行
- 画布页面：工具栏横向滚动、节点缩小、手机全屏操作
- 社区/资产库/工具页/数字人等全部17个页面补齐响应式断点
- 新增32条@media规则，媒体查询从107条增至139条

src/styles/pages/canvas.css

@@ -709,3 +709,96 @@
   right: -9999px;
   height: 1px;
 }
+
+/* ═══════════════════════════════════════════════════════
+   Responsive: Canvas
+   Breakpoints: 900px / 560px
+   ═══════════════════════════════════════════════════════ */
+
+/* ── 900px: Tablet — compact toolbar ── */
+@media (max-width: 900px) {
+  .studio-canvas-page {
+    flex-direction: column;
+  }
+
+  .studio-canvas-toolbar {
+    flex: 0 0 auto;
+    flex-direction: row;
+    width: 100%;
+    padding: 8px 12px;
+    gap: 6px;
+    overflow-x: auto;
+    border-right: none;
+    border-bottom: 1px solid var(--border-weak);
+    -webkit-overflow-scrolling: touch;
+  }
+
+  .studio-canvas-toolbar__group {
+    flex-direction: row;
+    flex-shrink: 0;
+    gap: 4px;
+  }
+
+  .studio-canvas-toolbar button {
+    min-width: 36px;
+    height: 36px;
+    font-size: 14px;
+  }
+
+  .studio-canvas-main {
+    flex: 1;
+    min-height: 0;
+  }
+
+  .studio-canvas-node {
+    min-width: 140px;
+    min-height: 60px;
+  }
+}
+
+/* ── 560px: Phone — fullscreen canvas ── */
+@media (max-width: 560px) {
+  .studio-canvas-page {
+    flex-direction: column;
+  }
+
+  .studio-canvas-toolbar {
+    flex: 0 0 auto;
+    padding: 6px 8px;
+    gap: 4px;
+    border-bottom: 1px solid var(--border-weak);
+  }
+
+  .studio-canvas-toolbar button {
+    min-width: 30px;
+    height: 30px;
+    padding: 0 6px;
+    font-size: 12px;
+    border-radius: 8px;
+  }
+
+  .studio-canvas-main {
+    flex: 1;
+    min-height: 0;
+  }
+
+  .studio-canvas-node {
+    min-width: 110px;
+    min-height: 48px;
+    border-radius: 10px;
+    padding: 8px;
+  }
+
+  .studio-canvas-project-bar {
+    right: 8px;
+    left: 8px;
+    bottom: 80px;
+    gap: 4px;
+    border-radius: 10px;
+    padding: 8px 10px;
+  }
+
+  .studio-canvas-project-bar__name-form {
+    font-size: 12px;
+  }
+}