feat(ui): 卡片可点进详情 + 身体年龄 + 运动详情 + 指标选择弹窗

需求 3.5 / 3.6 / 4.4 / 4.5 / 4.8 / 4.9

- 删掉导航栏右上角那两个 Link，就是它们渲染成半透明椭圆的。
  睡眠入口改为点健康页的睡眠卡片，每日入口移进趋势页内容里。
- 新增 lib/metrics.ts 作为唯一的指标注册表。label/unit/取值函数原本在
  今日、健康、趋势各写一份，改一处要改三处，也就有三次写不一致的机会。
- /metric/:id/ 指标详情：大数值 + 参考区间 + 7/30/90/365 趋势图 +
  平均最高最低达标天数 + 这个指标是什么 + 评分依据（取自后端，不在前端另写一份）
- /activity/:id/ 运动详情：概览/数据/分段/图表，数据分组照搬手表的排法，
  心率区间用单色顺序色阶（区间是有序刻度，不是分类，不能用分类色）
- /body-age/ 身体年龄：逐步展示 VO₂max 基准与各项修正，以及每步的出处
- 趋势页 15 个 chip 占满一屏且像张表单，改成弹窗选择，页面上只留一行摘要

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

client/src/services/api.ts

@@ -157,6 +157,98 @@ export interface ModelInfo {
   default: boolean;
 }
 
+export interface UserSettings {
+  heightCm: number | null;
+  weightKg: number | null;
+  birthDate: string | null;
+  sex: 'male' | 'female' | 'other' | null;
+  units: 'metric' | 'imperial';
+  autoSync: boolean;
+  autoSyncMinutes: number;
+  /** 0 means "everything Garmin has". */
+  historyDays: number;
+  age: number | null;
+  bmi: number | null;
+}
+
+export interface SettingsOptions {
+  sexes: string[];
+  units: string[];
+  autoSyncMinutes: number[];
+  historyDays: number[];
+}
+
+export interface BasisStep {
+  name: string;
+  detail: string;
+  source: string;
+}
+
+export interface RatingBasis {
+  fitnessAge: {
+    title: string;
+    summary: string;
+    steps: BasisStep[];
+    caveat: string;
+  };
+  bands: Array<{ metric: string; bands: string; source: string }>;
+  note: string;
+}
+
+export interface FitnessAge {
+  value: number | null;
+  chronologicalAge?: number;
+  delta?: number;
+  clamped?: boolean;
+  steps?: Array<{ label: string; input: string; years: number; kind: string }>;
+  missing: string[];
+  basis: RatingBasis['fitnessAge'];
+}
+
+export interface AutoSyncStatus {
+  enabled: boolean;
+  intervalSeconds: number;
+  tickSeconds: number;
+  days: number;
+  lastRunAt: string | null;
+  nextRunAt: string | null;
+  running: boolean;
+  account?: {
+    autoSync: boolean;
+    intervalMinutes: number;
+    dueAt: string | null;
+  };
+}
+
+/** One activity in full. Shapes mirror Garmin's own payload, which is why the
+ *  summary is left loosely typed — it carries dozens of optional fields that
+ *  differ by sport. */
+export interface ActivityDetail {
+  activityId: string;
+  activityName: string | null;
+  activityType: string | null;
+  summary: Record<string, number | string | null>;
+  laps: Array<{
+    index: number;
+    duration: number | null;
+    movingDuration: number | null;
+    distance: number | null;
+    averageSpeed: number | null;
+    maxSpeed: number | null;
+    calories: number | null;
+    averageHR: number | null;
+    maxHR: number | null;
+    elevationGain: number | null;
+    elevationLoss: number | null;
+  }>;
+  hrZones: Array<{ zone: number; seconds: number; lowBoundary: number | null }>;
+  weather: Record<string, any>;
+  gear: Array<Record<string, any>>;
+  exerciseSets: Array<Record<string, any>>;
+  series: Record<string, Array<number | null>>;
+  cached: boolean;
+}
+
 export interface TrendPoint {
   date: string;
   value: number;
@@ -349,6 +441,53 @@ class ApiClient {
     return data;
   }
 
+  // --- settings ---
+  async getSettings() {
+    const { data } = await this.client.get<UserSettings>('/settings');
+    return data;
+  }
+
+  async saveSettings(patch: Partial<UserSettings>) {
+    const { data } = await this.client.put<UserSettings>('/settings', patch);
+    return data;
+  }
+
+  async getSettingsOptions() {
+    const { data } = await this.client.get<SettingsOptions>('/settings/options');
+    return data;
+  }
+
+  async getRatingBasis() {
+    const { data } = await this.client.get<RatingBasis>('/settings/rating-basis');
+    return data;
+  }
+
+  async getFitnessAge() {
+    const { data } = await this.client.get<FitnessAge>('/health/fitness-age');
+    return data;
+  }
+
+  async getAutoSyncStatus() {
+    const { data } = await this.client.get<AutoSyncStatus>('/garmin/auto-sync');
+    return data;
+  }
+
+  /** Pull the last few days inline — fast enough to await, unlike a backfill. */
+  async syncLatest(days = 2) {
+    const { data } = await this.client.post<SyncResult>(
+      '/garmin/sync-latest', { days }
+    );
+    return data;
+  }
+
+  async getActivityDetail(activityId: string, refresh = false) {
+    const { data } = await this.client.get<ActivityDetail>(
+      `/garmin/activities/${activityId}/detail`,
+      { params: refresh ? { refresh: 1 } : {}, timeout: 60000 }
+    );
+    return data;
+  }
+
   async getBadges() {
     const { data } = await this.client.get<Badge[]>('/health/badges');
     return data;