fix: use API workdays and final delivery date in bot replies

capabilities/am516-delivery-prediction/docs/acceptance_samples.md

@@ -40,17 +40,18 @@ Expected:
 - record-table columns follow this order: 序号、记录时间、型号、推荐类型、差异项、API状态、AM516预测交期、可用库存、主导因素;
 - unavailable candidates remain in their original rule order and are recorded as `❌ 不存在` with unavailable result fields shown as `—`;
 
-## Sample 1B | Natural Days To Workdays
+## Sample 1B | API Workdays And Final Delivery Date
 
 Rules and expected results:
 
-- treat `AM516总交期`, or numeric `总交期` when the AM516 field is absent, as the original natural-day lead time `N`;
-- convert `N` with the approved quotient-and-remainder rule, including `r = 4` as one rest day and `r = 0` as no remainder workday;
-- exclude the local query date itself, then count the converted workdays using the configured China statutory workday calendar;
-- statutory holidays are excluded and official makeup weekend workdays are included;
-- for a query date of `2026-09-02`, `31` natural days convert to `22` workdays and produce `2026-10-09`;
-- output `2026-10-09（原始31个自然日，折算22个工作日）` instead of adding a separate National Day exception;
-- when counting reaches an unconfigured calendar year, do not silently fall back to a Monday-Friday estimate.
+- read `data.交期汇总.AM516工作日交期` and `data.交期汇总.AM516最终交货日期` directly;
+- when the API returns `8` and `2026-10-08`, output `AM516预测交期：8个工作日，最终交货日期：2026-10-08`;
+- use the same workdays-and-date form in the fastest-candidate summary, initial and continuation candidate details, and newly appended record rows;
+- ignore natural-day totals and the old `AM516预测交期` field when selecting the displayed result; do not recalculate workdays or dates locally;
+- a valid API date in another calendar year remains usable without a local holiday calendar;
+- accept zero workdays; reject negative, fractional, boolean, or non-numeric workday values and invalid dates;
+- if either new field is missing or invalid, report the lead-time result as unavailable instead of falling back to old fields or estimating;
+- choose the fastest candidate using the API workday count, even when the natural-day totals would rank candidates differently.
 
 ## Sample 1A | Continue With Other Candidates