feat: 优化 AI 教练聊天和打卡功能

- 在 AI 教练聊天界面中添加会话缓存功能，支持冷启动时恢复聊天记录
- 实现轻量防抖机制，确保会话变动时及时保存缓存
- 在打卡功能中集成按月加载打卡记录，提升用户体验
- 更新 Redux 状态管理，支持打卡记录的按月加载和缓存
- 新增打卡日历页面，允许用户查看每日打卡记录
- 优化样式以适应新功能的展示和交互

store/checkinSlice.ts

@@ -1,4 +1,4 @@
-import { createCheckin, fetchDailyCheckins, updateCheckin } from '@/services/checkins';
+import { createCheckin, fetchCheckinsInRange, fetchDailyCheckins, updateCheckin } from '@/services/checkins';
 import { createAsyncThunk, createSlice, PayloadAction } from '@reduxjs/toolkit';
 
 export type CheckinExercise = {
@@ -21,11 +21,13 @@ export type CheckinRecord = {
 export type CheckinState = {
   byDate: Record<string, CheckinRecord>;
   currentDate: string | null;
+  monthLoaded: Record<string, boolean>; // key: YYYY-MM, 标记该月数据是否已加载
 };
 
 const initialState: CheckinState = {
   byDate: {},
   currentDate: null,
+  monthLoaded: {},
 };
 
 function ensureRecord(state: CheckinState, date: string): CheckinRecord {
@@ -105,6 +107,14 @@ const checkinSlice = createSlice({
           items: mergedItems,
           note,
         };
+      })
+      .addCase(loadMonthCheckins.fulfilled, (state, action) => {
+        const monthKey = action.payload.monthKey;
+        const merged = action.payload.byDate;
+        for (const d of Object.keys(merged)) {
+          state.byDate[d] = merged[d];
+        }
+        state.monthLoaded[monthKey] = true;
       });
   },
 });
@@ -140,4 +150,61 @@ export const getDailyCheckins = createAsyncThunk('checkin/getDaily', async (date
   return { date, list } as { date?: string; list: any[] };
 });
 
+// 按月加载：优先使用区间接口，失败则逐日回退
+export const loadMonthCheckins = createAsyncThunk(
+  'checkin/loadMonth',
+  async (payload: { year: number; month1Based: number }, { getState }) => {
+    const { year, month1Based } = payload;
+    const pad = (n: number) => `${n}`.padStart(2, '0');
+    const monthKey = `${year}-${pad(month1Based)}`;
+
+    const start = `${year}-${pad(month1Based)}-01`;
+    const endDate = new Date(year, month1Based, 0).getDate();
+    const end = `${year}-${pad(month1Based)}-${pad(endDate)}`;
+
+    try {
+      const list = await fetchCheckinsInRange(start, end);
+      const byDate: Record<string, CheckinRecord> = {};
+      for (const rec of list) {
+        const date = rec?.checkinDate || rec?.date;
+        if (!date) continue;
+        const id = rec?.id ? String(rec.id) : `rec_${date}`;
+        const items = (rec?.metrics?.items ?? rec?.items) ?? [];
+        const note = typeof rec?.notes === 'string' ? rec.notes : undefined;
+        byDate[date] = { id, date, items, note };
+      }
+      return { monthKey, byDate } as { monthKey: string; byDate: Record<string, CheckinRecord> };
+    } catch {
+      // 回退逐日请求（并行）
+      const endNum = new Date(year, month1Based, 0).getDate();
+      const dates = Array.from({ length: endNum }, (_, i) => `${year}-${pad(month1Based)}-${pad(i + 1)}`);
+      const results = await Promise.all(
+        dates.map(async (d) => ({ d, list: await fetchDailyCheckins(d) }))
+      );
+      const byDate: Record<string, CheckinRecord> = {};
+      for (const { d, list } of results) {
+        let items: CheckinExercise[] = [];
+        let note: string | undefined;
+        let id: string | undefined;
+        for (const rec of list) {
+          if (rec?.id && !id) id = String(rec.id);
+          const metricsItems = rec?.metrics?.items ?? rec?.items;
+          if (Array.isArray(metricsItems)) items = metricsItems as CheckinExercise[];
+          if (typeof rec?.notes === 'string') note = rec.notes as string;
+        }
+        byDate[d] = { id: id || `rec_${d}`, date: d, items, note };
+      }
+      return { monthKey, byDate } as { monthKey: string; byDate: Record<string, CheckinRecord> };
+    }
+  },
+  {
+    condition: (payload, { getState }) => {
+      const state = getState() as any;
+      const pad = (n: number) => `${n}`.padStart(2, '0');
+      const monthKey = `${payload.year}-${pad(payload.month1Based)}`;
+      return !state?.checkin?.monthLoaded?.[monthKey];
+    },
+  }
+);
+