Fix time entry 500 and inventory edit pencil visibility

- Remove parseInt() from time entry worker select — GUIDs were destroyed
  to NaN → sent as null → FindByIdAsync(null) threw 500
- Ledger pencil: also show for Adjustment rows (no PO) so scan-without-job
  entries get an edit button, not just JobUsage rows
- InventoryController: always write JobUsage type for scan-based logs;
  accept Adjustment in edit endpoints; promote Adjustment→JobUsage when
  a job is assigned via edit

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

src/PowderCoating.Web/Views/Jobs/Details.cshtml

@@ -2795,7 +2795,7 @@
 
         async function save() {
             const id = parseInt(document.getElementById('teEntryId').value);
-            const workerId = parseInt(document.getElementById('teWorkerId').value);
+            const workerId = document.getElementById('teWorkerId').value;
             const workDate = document.getElementById('teWorkDate').value;
             const hours = parseFloat(document.getElementById('teHoursWorked').value);
             const stage = document.getElementById('teStage').value.trim();