fix: 振动定时器清理、完成保存守卫、暗黑冷启动、头像云存储

- timer: 振动 setTimeout 入栈追踪,暂停/停止/卸载/重练统一清理,
  避免页面销毁后残留震动(_clearVibrateTimers)
- timer: _saving 守卫统一到 _saveAndShowCompletion,自然完成与手动
  结束两路径都防重复保存;修复 onTrainAgain 不重置会话状态导致
  再练一次后第二次无语音/振动且保存被挡
- app.wxss: @media dark 补全 --text/--card-bg/--bg-soft/--border/
  --success/--danger,冷启动即为完整深色,不再背景深卡片白的割裂闪烁
- settings: 头像优先上传云存储存 fileID,三级回退(fileID->base64->
  临时URL),pushAll 不再每次传输图片字节

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pages/timer/timer.js

@@ -94,6 +94,7 @@ Page({
     this._lastMinuteAt = 0
     this._lastCountdown = 0
     this._saving = false
+    this._clearVibrateTimers()
 
     this._timer = new Timer({
       onTick: (tick) => {
@@ -135,7 +136,14 @@ Page({
       if (!s.vibrate) return
       try {
         for (let i = 0; i < n; i++) {
-          setTimeout(() => wx.vibrateShort(), i * (ms + 30))
+          // Track timers so pause/stop/unload can cancel pending bursts
+          // instead of firing vibrations on a page that's already torn down.
+          const id = setTimeout(() => {
+            wx.vibrateShort()
+            const idx = this._vibrateTimers.indexOf(id)
+            if (idx > -1) this._vibrateTimers.splice(idx, 1)
+          }, i * (ms + 30))
+          this._vibrateTimers.push(id)
         }
       } catch (e) {}
     }
@@ -174,6 +182,19 @@ Page({
     }
   },
 
+  /**
+   * Cancel any pending vibration timers. Tracked so pause/stop/unload can
+   * abort scheduled bursts instead of firing on a torn-down page.
+   */
+  _clearVibrateTimers() {
+    if (!this._vibrateTimers) {
+      this._vibrateTimers = []
+      return
+    }
+    this._vibrateTimers.forEach((id) => clearTimeout(id))
+    this._vibrateTimers = []
+  },
+
   /**
    * Detect which celebration level to show. Called at onComplete (BEFORE
    * saveRecord fires in finishTraining), so stats reflect pre-save state.
@@ -224,6 +245,7 @@ Page({
   onUnload() {
     voice.stop()
     voice.destroy()
+    this._clearVibrateTimers()
     if (this._timer) {
       this._timer.stop()
       this._timer = null
@@ -257,6 +279,7 @@ Page({
     if (!this.data.isRunning || this.data.isPaused) return
     this._timer.pause()
     voice.stop()
+    this._clearVibrateTimers()
     this.setData({ isPaused: true, status: 'paused' })
   },
 
@@ -281,11 +304,10 @@ Page({
     // a second tap on the underlying 结束 button is harmless — but we
     // still need to guard the save itself.
     if (this._saving) return
-    this._saving = true
 
     const elapsed = this._timer.stop()
+    this._clearVibrateTimers()
     if (elapsed < 3) {
-      this._saving = false
       wx.showToast({ title: '训练时间太短', icon: 'none', duration: 1500 })
       setTimeout(() => { wx.navigateBack() }, 1500)
       return
@@ -300,6 +322,11 @@ Page({
    * pre-save stats so the level is decided before the data changes.
    */
   _saveAndShowCompletion(elapsed) {
+    // Unified re-entry guard: covers both the natural-complete (onComplete)
+    // and manual-stop (finishTraining) paths so the save never runs twice.
+    if (this._saving) return
+    this._saving = true
+
     const { level, message } = this._detectCelebrationLevel(elapsed)
     const confettiPieces = this._buildConfettiPieces(level)
 
@@ -377,6 +404,15 @@ Page({
       this._completionCountUp.cancel()
       this._completionCountUp = null
     }
+    // Reset per-session state so the next run fires reminders/saves
+    // correctly (previously these stayed set, muting cues on the 2nd run).
+    this._saving = false
+    this._halfwaySignaled = false
+    this._last30Signaled = false
+    this._last10Signaled = false
+    this._lastMinuteAt = 0
+    this._lastCountdown = 0
+    this._clearVibrateTimers()
     this.setData({
       showCompletion: false,
       isCompleted: false,