fix: address audit findings — fitting trigger, race guards, state conflicts

wear-check:
- Send weak pulse light (brightness=26) to trigger FFE4 fitting report
- Timeout degrades to pass (backward compat with 17-byte firmware)
- Sync _resolved flag prevents double-resolve

treating:
- Only treat run_state=0x00 as completion after seeing run_state=0x02
  (prevents false completion on startup)
- Sync _finishing flag replaces async data.completed for race prevention
- onStatus preserves paused state during fitting loss (|| fittingLost)
- Remove dead _fittingTimer reference from onUnload

auto-scan:
- Sync _completed flag in _scanComplete prevents double-build

miniprogram/pages/wear-check/wear-check.js

@@ -42,6 +42,7 @@ Page({
   checkWearing: function () {
     var self = this
     self._cleanup()
+    self._resolved = false
     self.setData({ checking: true, result: null, error: '' })
 
     if (!ble.isConnected()) {
@@ -57,18 +58,32 @@ Page({
     ble.on('battery', self._onBattery)
 
     self._onFitting = function (data) {
+      if (self._resolved) return
       console.log('[WEAR] 贴合状态:', data.fitting)
       if (data.fitting === 1) {
+        self._resolved = true
         self._cleanup()
         self.setData({ checking: false, result: 'ok' })
       }
     }
     ble.on('fitting', self._onFitting)
 
+    ble.setParams({
+      region_mask: 0x1F,
+      wavelength: 2,
+      brightness: 26,
+      hold_time: 0,
+      control: 0x01
+    }).then(function () {
+      console.log('[WEAR] 微弱光贴合检测指令已发送')
+    }).catch(function () {})
+
     self._fittingTimer = setTimeout(function () {
-      if (self.data.result) return
+      if (self._resolved) return
+      self._resolved = true
       self._cleanup()
-      self.setData({ checking: false, result: 'fail', error: '未检测到贴合，请确认设备已正确佩戴' })
+      console.log('[WEAR] 超时未收到 fitting 事件，降级为通过（兼容旧固件）')
+      self.setData({ checking: false, result: 'ok' })
     }, FITTING_TIMEOUT)
   },