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)

custom-tab-bar/index.wxml

@@ -4,12 +4,7 @@
     data-index="0"
     bindtap="switchTab"
   >
-    <view class="tab-icon">
-      <view class="icon-home {{selected === 0 ? 'active' : ''}}">
-        <view class="home-roof"></view>
-        <view class="home-body"></view>
-      </view>
-    </view>
+    <view class="tab-icon" style="background-image: url({{selected === 0 ? svgIcons.homeFill : svgIcons.home}})"></view>
     <text class="tab-text">训练</text>
   </view>
 
@@ -18,13 +13,7 @@
     data-index="1"
     bindtap="switchTab"
   >
-    <view class="tab-icon">
-      <view class="icon-records {{selected === 1 ? 'active' : ''}}">
-        <view class="bar bar1"></view>
-        <view class="bar bar2"></view>
-        <view class="bar bar3"></view>
-      </view>
-    </view>
+    <view class="tab-icon" style="background-image: url({{selected === 1 ? svgIcons.calendarFill : svgIcons.calendar}})"></view>
     <text class="tab-text">记录</text>
   </view>
 
@@ -33,12 +22,16 @@
     data-index="2"
     bindtap="switchTab"
   >
-    <view class="tab-icon">
-      <view class="icon-settings {{selected === 2 ? 'active' : ''}}">
-        <view class="gear-outer"></view>
-        <view class="gear-center"></view>
-      </view>
-    </view>
+    <view class="tab-icon" style="background-image: url({{selected === 2 ? svgIcons.rankFill : svgIcons.rank}})"></view>
+    <text class="tab-text">排行</text>
+  </view>
+
+  <view
+    class="tab-item {{selected === 3 ? 'active' : ''}}"
+    data-index="3"
+    bindtap="switchTab"
+  >
+    <view class="tab-icon" style="background-image: url({{selected === 3 ? svgIcons.settingsFill : svgIcons.settings}})"></view>
     <text class="tab-text">设置</text>
   </view>
 </view>