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)

utils/voice.js

@@ -0,0 +1,94 @@
+/**
+ * Voice prompt utility for the timer.
+ *
+ * 4 fixed, polished prompts live in `cloudfunctions/tts`. We call that
+ * cloud function with a key, get back an audio URL (cached in cloud
+ * storage after first synthesis), and play it via createInnerAudioContext.
+ *
+ * The in-memory `_urlCache` avoids hitting the cloud function more than
+ * once per prompt per session. The audio context is a singleton so
+ * overlapping prompts interrupt each other cleanly.
+ *
+ * If the cloud function is unconfigured (no TTS credentials) and returns
+ * `success: false`, we fall back to a silent no-op — better than spamming
+ * the user with toast errors mid-plank.
+ */
+
+const PROMPTS = {
+  halfway: '已完成一半啦,坚持就是胜利!',
+  last30: '最后30秒,保持呼吸,稳住姿势!',
+  last10: '最后10秒,再加把劲!',
+  complete: '太棒了!今天的目标已完成,继续加油!'
+}
+
+let _ctx = null
+const _urlCache = {}     // { promptKey: audioUrl }
+
+const _getCtx = () => {
+  if (!_ctx) {
+    _ctx = wx.createInnerAudioContext()
+    // Play even when the device is in silent mode — we want the user to
+    // actually hear training cues during a session.
+    _ctx.obeyMuteSwitch = false
+  }
+  return _ctx
+}
+
+const _fetchUrl = async (promptKey) => {
+  if (_urlCache[promptKey]) return _urlCache[promptKey]
+  try {
+    const res = await wx.cloud.callFunction({
+      name: 'tts',
+      data: { promptKey },
+      // Default WeChat cloud timeout is 3s, which is exactly the TTS
+      // first-call budget (synth + upload + tempURL). Bump to 30s for
+      // cold starts; cached calls return in <500ms.
+      config: { timeout: 30000 }
+    })
+    if (res && res.result && res.result.success && res.result.audioUrl) {
+      _urlCache[promptKey] = res.result.audioUrl
+      return res.result.audioUrl
+    }
+  } catch (e) {
+    // cloud function not deployed or other error — silent fallback
+  }
+  return null
+}
+
+/**
+ * Play a prompt. Returns a Promise that resolves when playback starts
+ * (or immediately if there's no audio available).
+ */
+const play = async (promptKey) => {
+  if (!PROMPTS[promptKey]) return
+  const url = await _fetchUrl(promptKey)
+  if (!url) return
+  const ctx = _getCtx()
+  try {
+    ctx.stop()
+    ctx.src = url
+    ctx.play()
+  } catch (e) { /* ignore playback errors */ }
+}
+
+/**
+ * Stop any currently-playing voice prompt. Call this when the user
+ * pauses/stops/finishes training to avoid stray audio.
+ */
+const stop = () => {
+  if (_ctx) {
+    try { _ctx.stop() } catch (e) { /* ignore */ }
+  }
+}
+
+/**
+ * Tear down the audio context. Call on page unload.
+ */
+const destroy = () => {
+  if (_ctx) {
+    try { _ctx.destroy() } catch (e) { /* ignore */ }
+    _ctx = null
+  }
+}
+
+module.exports = { play, stop, destroy, PROMPTS }