fix: get_pay_fee 返回 fee_rate 而非 fee_rate*amount，修复双重乘法

get_pay_fee() 返回 fee_rate*amount，但 create_payment()
又把返回值当 feerate 传给 new_log()，new_log() 内部又乘
一次 amount，导致 pay_fee = fee_rate * amount²。

修复：
- get_pay_fee() 改为只返回 fee_rate
- create_payment() 自己计算 fee = feerate * amount
- new_log() 传 feerate 而非 fee

unipay/init.py

@@ -105,7 +105,8 @@ async def create_payment(request, params_kw=None):
 			raise e
 		notify_url = env.entire_url(f'notify/{provider}')
 		pl = PaymentLog(request._run_ns)
-		fee = await get_pay_fee(provider, data.amount)
+		feerate = await get_pay_fee(provider, data.amount)
+		fee = feerate * data.amount
 		channel = get_provider_channel(provider)
 		userid = await env.get_user()
 		orgid = await env.get_userorgid()
@@ -116,7 +117,7 @@ async def create_payment(request, params_kw=None):
 		currency = data.currency
 		plog = await pl.new_log(userid, orgid, provider, 
 						amount, 
-						fee, client_ip, currency=currency)
+						feerate, client_ip, currency=currency)
 		if plog:
 			data.out_trade_no = plog.id
 			data.customerid = orgid

unipay/payfee.py

@@ -81,5 +81,5 @@ async def sor_get_pay_fee(sor, providerid, amount):
 		exception(f'Exception:{e}')
 		rec.fee_rate = 0.00
 	debug(f'{rec=}, {rec.fee_rate=}, {amount=}')
-	return rec.fee_rate * amount
+	return rec.fee_rate