feat(app): add lesson-plans, practice, and grade dashboard routes

- Add admin/lesson-plans, parent/lesson-plans, student/lesson-plans routes

- Add student/practice and teacher/practice routes for adaptive practice

- Add management/grade/dashboard and management/grade/practice routes

- Add teacher/lesson-plans error and loading boundaries

- Update existing admin, parent, student, teacher pages with new features

- Update globals.css and proxy middleware

src/app/globals.css

@@ -149,6 +149,21 @@
   --color-sidebar-border: hsl(var(--sidebar-border));
   --color-sidebar-ring: hsl(var(--sidebar-ring));
 
+  /* Material Design 3 Surface 令牌映射（备课模块使用）*/
+  --color-surface: hsl(var(--card));
+  --color-on-surface: hsl(var(--foreground));
+  --color-on-surface-variant: hsl(var(--muted-foreground));
+  --color-surface-container-lowest: hsl(var(--background));
+  --color-surface-container-low: hsl(var(--muted));
+  --color-surface-container: hsl(var(--secondary));
+  --color-surface-container-high: hsl(var(--accent));
+  --color-surface-container-highest: hsl(var(--muted-foreground));
+  --color-outline-variant: hsl(var(--border));
+  --color-outline: hsl(var(--border));
+  --color-error: hsl(var(--destructive));
+  --color-tertiary: hsl(var(--chart-3));
+  --color-tertiary-container: hsl(var(--chart-3));
+
   --radius-lg: var(--radius);
   --radius-md: calc(var(--radius) - 2px);
   --radius-sm: calc(var(--radius) - 4px);
@@ -241,3 +256,9 @@
 .anchor-edge.active {
   opacity: 1;
 }
+
+/* 正文节点光标指示器闪烁 */
+@keyframes cursor-blink {
+  0%, 50% { opacity: 1; }
+  51%, 100% { opacity: 0; }
+}