fix(missing-skus): reconcile stale false positives against Oracle

SKUs mapped externally (via SSH script or direct SQL) never triggered
resolve_missing_sku(), leaving them stuck as unresolved=0 indefinitely.
New reconcile_unresolved_missing_skus() revalidates ALL unresolved SKUs
against Oracle at sync, rescan, and CSV import time. Fail-soft on Oracle
down. Clears the 7 prod false positives on next sync or manual rescan.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/app/routers/validation.py

@@ -58,6 +58,8 @@ async def scan_and_validate():
         if tracked:
             new_missing += 1
 
+    rec = await validation_service.reconcile_unresolved_missing_skus()
+
     total_skus_scanned = len(all_skus)
     new_missing_count = len(result["missing"])
     unchanged = total_skus_scanned - new_missing_count
@@ -72,7 +74,7 @@ async def scan_and_validate():
         # Fields consumed by the rescan progress banner in missing_skus.html
         "total_skus_scanned": total_skus_scanned,
         "new_missing": new_missing_count,
-        "auto_resolved": 0,
+        "auto_resolved": rec["resolved"],
         "unchanged": unchanged,
         "skus": {
             "mapped": len(result["mapped"]),