feat(db_compare): add PostgreSQL-based comparison engine with SF handling

Replace Excel-based undelivered comparison with DB queries for all four
sites. The engine anchors on actual scan_time, reverse-lookups handover
batches, and compares expected vs actual waybill-by-waybill.

Shunxin SF waybills: use COUNT(*) instead of COUNT(DISTINCT piece_no)
since SF piece numbers are random and not derivable from the waybill.

Changes:
- db_compare.py: new module with compare_site_date(), compare_site_batch(),
  write_result_excel(), and POST /compare API endpoint
- runtime.py: switch _site_undelivered_handler from compare.write_site_file
  (Excel) to db_compare (DB); downloads succeed independently of comparison
- server.py: add POST /compare endpoint with date validation
- docs: implementation plan for Shunxin DB comparison

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

inbound_verify/cli/server.py

@@ -36,6 +36,7 @@ from inbound_verify.runtime import (
     launch_and_prepare,
     run_heartbeat,
 )
+from inbound_verify import db_compare
 
 # 全部站点；百世固定下载当天，不可配置偏移
 ALL_SITES = ["顺心", "百世", "中通", "韵达", "安能"]
@@ -245,6 +246,71 @@ def list_tasks(limit: int = 20):
     return state_store.list_tasks(limit)
 
 
+# ── DB 比对（基于 PostgreSQL，不依赖 Excel 文件）──
+
+
+class CompareRequest(BaseModel):
+    site: str
+    date: str  # YYYY-MM-DD
+
+
+@app.post("/compare")
+def run_compare(req: CompareRequest):
+    """DB 差缺比对：以实到扫描日期为锚点，反推交接批次，展开全量比对。
+    返回统计指标 + 差缺明细。
+    """
+    # 合法性校验
+    if req.site not in db_compare.SITE_COMPARE_CONFIG:
+        raise HTTPException(
+            status_code=400,
+            detail=f"不支持的站点: {req.site}（支持: {list(db_compare.SITE_COMPARE_CONFIG.keys())}）",
+        )
+    try:
+        target_date = datetime.strptime(req.date, "%Y-%m-%d").date()
+    except ValueError:
+        raise HTTPException(
+            status_code=400, detail=f"date 格式非法，需 YYYY-MM-DD: {req.date}"
+        )
+    today = datetime.now().date()
+    if target_date > today:
+        raise HTTPException(status_code=400, detail=f"date 不可为未来日期: {req.date}")
+
+    result = db_compare.compare_site_date(req.site, req.date)
+    if result is None:
+        raise HTTPException(
+            status_code=404,
+            detail=f"{req.site} {req.date}: 当天无实到数据，无法比对",
+        )
+
+    return {
+        "site": result.site,
+        "date": result.date,
+        "batches": result.batches,
+        "stats": {
+            "waybill_count": result.stats.waybill_count,
+            "sf_wb_count": result.stats.sf_wb_count,
+            "expected_pieces": result.stats.expected_pieces,
+            "arrived_pieces": result.stats.arrived_pieces,
+            "undelivered_pieces": result.stats.undelivered_pieces,
+            "undelivered_wb": result.stats.undelivered_wb,
+            "full_miss": result.stats.full_miss,
+            "part_miss": result.stats.part_miss,
+            "sf_undelivered": result.stats.sf_undelivered,
+        },
+        "rows": [
+            {
+                "handover_no": r.handover_no,
+                "waybill_no": r.waybill_no,
+                "total_pieces": r.total_pieces,
+                "arrived_pieces": r.arrived_pieces,
+                "arrived_list": r.arrived_list,
+                "is_sf": r.is_sf,
+            }
+            for r in result.rows
+        ],
+    }
+
+
 @app.get("/status")
 def get_status():
     """各站登录态 + 数据态 + 入库态（前端状态盘用），另含 worker 就绪状态。"""