feat: select school terms and smooth refractive Dock motion

mobile/lib/features/timetable/timetable_page.dart

@@ -3,11 +3,13 @@ import 'package:flutter/material.dart';
 import '../../app/app_controller.dart';
 import '../../app/app_theme.dart';
 import '../../domain/schedule_engine.dart';
+import '../profile/settings_page.dart';
 import 'week_grid.dart';
 
 class TimetablePage extends StatefulWidget {
-  const TimetablePage({super.key, required this.controller});
+  const TimetablePage({super.key, required this.controller, this.onSync});
   final AppController controller;
+  final VoidCallback? onSync;
   @override
   State<TimetablePage> createState() => _TimetablePageState();
 }
@@ -40,13 +42,32 @@ class _TimetablePageState extends State<TimetablePage> {
         140 + MediaQuery.paddingOf(context).bottom,
       ),
       children: [
-        const Padding(
+        Padding(
           padding: EdgeInsets.symmetric(horizontal: 14),
-          child: Text(
-            'RSchedule',
-            style: TextStyle(fontSize: 22, fontWeight: FontWeight.w700),
+          child: Row(
+            children: [
+              const Expanded(
+                child: Text(
+                  '课表',
+                  style: TextStyle(fontSize: 22, fontWeight: FontWeight.w700),
+                ),
+              ),
+              IconButton(
+                tooltip: '刷新课表',
+                onPressed: widget.onSync,
+                icon: const Icon(Icons.sync_rounded),
+              ),
+            ],
           ),
         ),
+        if (!c.isDemo && c.snapshot.schoolTerm != null)
+          Padding(
+            padding: const EdgeInsets.fromLTRB(14, 0, 14, 8),
+            child: Text(
+              c.snapshot.schoolTerm!.label,
+              style: TextStyle(fontSize: 12, color: ink.withValues(alpha: 0.5)),
+            ),
+          ),
         const SizedBox(height: 10),
         SurfaceCard(
           padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 0),
@@ -142,6 +163,51 @@ class _TimetablePageState extends State<TimetablePage> {
             textAlign: TextAlign.center,
             style: TextStyle(fontSize: 11, color: ink.withValues(alpha: 0.35)),
           ),
+        ] else if (c.visibleCourses.isNotEmpty) ...[
+          const SizedBox(height: 36),
+          Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 14),
+            child: SurfaceCard(
+              child: Column(
+                children: [
+                  const Icon(
+                    Icons.event_available_rounded,
+                    size: 44,
+                    color: river,
+                  ),
+                  const SizedBox(height: 18),
+                  const Text(
+                    '课表已导入，请设置学期开始日',
+                    textAlign: TextAlign.center,
+                    style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600),
+                  ),
+                  const SizedBox(height: 10),
+                  Text(
+                    '${c.visibleCourses.length} 条课程安排已保存',
+                    style: const TextStyle(fontSize: 13, color: river),
+                  ),
+                  const SizedBox(height: 10),
+                  const Text(
+                    '课程按教学周保存。设置真实的学期开始日后，\n才能显示每周课表并安排课前提醒。',
+                    textAlign: TextAlign.center,
+                    style: TextStyle(fontSize: 12, height: 1.8),
+                  ),
+                  const SizedBox(height: 20),
+                  FilledButton.icon(
+                    onPressed: () => Navigator.push(
+                      context,
+                      MaterialPageRoute<void>(
+                        builder: (_) =>
+                            SettingsPage(controller: c, focusSemester: true),
+                      ),
+                    ),
+                    icon: const Icon(Icons.edit_calendar_rounded, size: 18),
+                    label: const Text('设置学期开始日'),
+                  ),
+                ],
+              ),
+            ),
+          ),
         ] else ...[
           const SizedBox(height: 38),
           const Icon(