fix(srm): 修复简易版确认中标投标金额为空时系统异常

- confirmTenderProject 中 award_amount 直接取 bidTotalAmount,投标金额为空时违反 srm_bid_award.award_amount NOT NULL 约束,抛 DataIntegrityViolationException 返回系统异常
- 新增 resolveAwardAmount:投标金额为空时回退汇总该投标下所有报价作为中标金额
- generatePurchaseOrderForSimple 防御 quotePrice 为空、quantity 为空或为 0 导致 NPE/除零

Co-Authored-By: Claude <noreply@anthropic.com>