feat: v1.5 — plan editor, voice prompts, UI polish

Major features:
- Training plan editor: edit preset days/duration per plan (in-place
  override via custom_plans storage; preset ids preserved so existing
  records stay valid)
- Voice prompts at 4 fixed points during training (halfway / 30s /
  10s / done) via Tencent Cloud TTS (cloudfunctions/tts + utils/voice.js)
- Free-training button: switched from outline (transparent) to ghost
  variant (theme-tinted) for visual weight

Bug fixes:
- 4 functional pages: SVG data URIs failed to render in WeChat because
  '\#' in colors was parsed as a data-URI fragment delimiter. encode the
  whole SVG via encodeURIComponent in utils/icons.js build().
- Old records (saved before id field was added) could not be deleted
  (data-id was empty, triggered defensive guard). Backfill stable
  legacy-<month>-<index>-<duration> ids in getRecords() and persist.
- settings.js plan-row editor button event was bubbling up to the row's
  bindtap (which also fired onSelectPlan). Wrapped in catch:tap.

UI:
- Settings page: 3 hardcoded plans replaced with dynamic buildPlansList
  that overlays custom_plans on top of presets
- Plan editor: bottom-sheet modal in settings page (regular view, not
  ui-modal — WeChat custom component root element drops position:fixed
  in this runtime)
- Free-training button: rounded pill style, full-width, 24rpx gap from
  primary action; bottom sheet uses max-height: 88vh + internal scroll
- Version bumped to v1.5, last updated 2026-06-10

Removed:
- Daily reminder section (dailyReminder / reminderTime) — replaced by
  the 4 voice prompts which cover the same user need without requiring
  long-term scheduling that WeChat mini-programs can't actually do

Misc:
- utils/plan.js refactored to formula-driven: presets declare
  totalDays/startTarget/increment/cycleDays, days[] is generated. Same
  formula applies to custom plans.
- Timer _remind() guards each prompt on minimum duration so short
  free-mode sessions don't fire 'last30' at the start
- Cloud storage cloud_plans field added to data push payload; restored
  on first install via _restoreFromCloud
- .gitignore added for local AI tool caches (.reasonix/, reasonix.toml,
  .codegraph/daemon.pid)

pages/timer/timer.wxml

@@ -30,7 +30,7 @@
     </view>
 
     <view class="overtime-badge" wx:if="{{isCompleted && overtime > 0}}">
-      <text class="overtime-icon">🔥</text>
+      <image class="overtime-icon" src="{{icons.hotFill}}" mode="aspectFit"></image>
       <text>+{{overtime}}s</text>
     </view>
   </view>
@@ -38,58 +38,64 @@
   <!-- 状态提示 -->
   <view class="hint-section">
     <view class="hint-row" wx:if="{{status === 'idle'}}">
-      <text class="hint-emoji">🧘</text>
+      <image class="hint-icon" src="{{icons.targetFill}}" mode="aspectFit"></image>
       <text class="hint-text">
         <block wx:if="{{isFreeMode}}">自由训练 · 目标 {{duration}} 秒</block>
         <block wx:else>今日目标 {{duration}} 秒 · 第 {{planDay}} 天</block>
       </text>
     </view>
     <view class="hint-row" wx:elif="{{status === 'running'}}">
-      <text class="hint-emoji running-pulse">💪</text>
+      <image class="hint-icon running-pulse" src="{{icons.likeFill}}" mode="aspectFit"></image>
       <text class="hint-text running">保持姿势，核心收紧!</text>
     </view>
     <view class="hint-row" wx:elif="{{status === 'paused'}}">
-      <text class="hint-emoji">⏸</text>
+      <image class="hint-icon" src="{{icons.notificationForbidFill}}" mode="aspectFit"></image>
       <text class="hint-text paused">已暂停</text>
     </view>
     <view class="hint-row completed-hint" wx:elif="{{status === 'completed'}}">
-      <text class="hint-emoji completed-bounce">🎉</text>
+      <image class="hint-icon completed-bounce" src="{{icons.roundCheckFill}}" mode="aspectFit"></image>
       <text class="hint-text completed">目标完成! 继续坚持!</text>
     </view>
   </view>
 
   <!-- 控制按钮 -->
   <view class="controls">
-    <button
+    <ui-btn
       wx:if="{{!isRunning && !isPaused}}"
-      class="ctrl-btn start-btn"
+      variant="primary"
+      size="xl"
+      block
+      text="开始"
+      icon-src="{{icons.playFill}}"
       bindtap="onStart"
-    >
-      <text class="ctrl-icon">▶</text>
-      <text>开始</text>
-    </button>
+    ></ui-btn>
 
     <view class="ctrl-row" wx:if="{{isRunning || isPaused}}">
-      <button
+      <ui-btn
         wx:if="{{!isPaused}}"
-        class="ctrl-btn pause-btn"
+        variant="ghost"
+        size="xl"
+        text="暂停"
+        icon-src="{{icons.notificationForbidFill}}"
+        custom-style="margin-right: 28rpx;"
         bindtap="onPause"
-      >
-        <text class="ctrl-icon">⏸</text>
-        <text>暂停</text>
-      </button>
-      <button
+      ></ui-btn>
+      <ui-btn
         wx:if="{{isPaused}}"
-        class="ctrl-btn resume-btn"
+        variant="primary"
+        size="xl"
+        text="继续"
+        icon-src="{{icons.playFill}}"
+        custom-style="margin-right: 28rpx;"
         bindtap="onStart"
-      >
-        <text class="ctrl-icon">▶</text>
-        <text>继续</text>
-      </button>
-      <button class="ctrl-btn stop-btn" bindtap="onStop">
-        <text class="ctrl-icon">⏹</text>
-        <text>结束</text>
-      </button>
+      ></ui-btn>
+      <ui-btn
+        variant="outline"
+        size="xl"
+        text="结束"
+        icon-src="{{icons.stop}}"
+        bindtap="onStop"
+      ></ui-btn>
     </view>
   </view>
 </view>