fix: add ble.js proxy for WeChat miniprogram module resolution

WeChat's require() does not support directory imports — require('./ble')
looks for ble.js, not ble/index.js. Add a proxy file that re-exports
from ble/index.js so all existing imports continue to work.

miniprogram/services/ble.js

@@ -0,0 +1 @@
+module.exports = require('./ble/index')