Fix material usage logging: remaining weight mode, edit modal, and consolidate duplicate logic

- InventoryController: extract RecordInventoryUsageAsync helper; both LogUsage
  (scan page) and LogMaterial (jobs modal, moved from JobsController) call it —
  no more duplicate save/GL logic across two controllers
- Log Material modal: replace radio buttons with prominent toggle buttons so the
  active mode (Amount Used vs Amount Remaining) is always visually obvious; add
  always-visible preview line showing exactly what will be logged before saving
- Edit Usage modal: add quantity field (pre-populated from existing transaction)
  with delta adjustment to InventoryItem.QuantityOnHand on save; include
  completed/terminal jobs in the dropdown so entries can be corrected after a
  job is marked done
- Scan page job picker: include jobs completed within the last 7 days (marked
  with '(completed)') so usage can be logged after a job is finished

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

src/PowderCoating.Web/Controllers/JobsController.cs

@@ -4399,75 +4399,7 @@ public class JobsController : Controller
         _logger.LogInformation("Recorded first job creation for company {CompanyId}", companyId);
     }
 
-    /// <summary>
-    /// Logs manual material usage from the job details page. Mirrors the QR scan LogUsage
-    /// flow in InventoryController but returns JSON so the modal can close and refresh inline.
-    /// Quantity is always the amount USED (caller converts from remaining if needed).
-    /// </summary>
-    [HttpPost]
-    [ValidateAntiForgeryToken]
-    public async Task<IActionResult> LogMaterial([FromBody] LogMaterialRequest req)
-    {
-        try
-        {
-            if (req.QuantityUsed <= 0)
-                return Json(new { success = false, message = "Quantity used must be greater than zero." });
-
-            var item = await _unitOfWork.InventoryItems.GetByIdAsync(req.InventoryItemId);
-            if (item == null) return Json(new { success = false, message = "Inventory item not found." });
-
-            var job = await _unitOfWork.Jobs.GetByIdAsync(req.JobId);
-            if (job == null) return Json(new { success = false, message = "Job not found." });
-
-            var txnType = req.TransactionType == "Waste"
-                ? InventoryTransactionType.Waste
-                : InventoryTransactionType.JobUsage;
-
-            item.QuantityOnHand -= req.QuantityUsed;
-            item.UpdatedAt = DateTime.UtcNow;
-            await _unitOfWork.InventoryItems.UpdateAsync(item);
-
-            var txn = new PowderCoating.Core.Entities.InventoryTransaction
-            {
-                InventoryItemId = item.Id,
-                TransactionType = txnType,
-                Quantity        = -req.QuantityUsed,
-                UnitCost        = item.UnitCost,
-                TotalCost       = req.QuantityUsed * item.UnitCost,
-                TransactionDate = DateTime.UtcNow,
-                BalanceAfter    = item.QuantityOnHand,
-                JobId           = req.JobId,
-                Reference       = $"Job {job.JobNumber}",
-                Notes           = req.Notes?.Trim(),
-                CompanyId       = item.CompanyId,
-                CreatedAt       = DateTime.UtcNow
-            };
-            await _unitOfWork.InventoryTransactions.AddAsync(txn);
-            await _unitOfWork.CompleteAsync();
-
-            // GL: DR COGS, CR Inventory Asset
-            if (item.CogsAccountId.HasValue && item.InventoryAccountId.HasValue)
-            {
-                var cost = req.QuantityUsed * (item.AverageCost > 0 ? item.AverageCost : item.UnitCost);
-                await _accountBalanceService.DebitAsync(item.CogsAccountId, cost);
-                await _accountBalanceService.CreditAsync(item.InventoryAccountId, cost);
-            }
-
-            return Json(new
-            {
-                success    = true,
-                message    = $"Logged {req.QuantityUsed:N2} {item.UnitOfMeasure} of {item.Name}.",
-                newBalance = item.QuantityOnHand,
-                unitOfMeasure = item.UnitOfMeasure,
-                itemName   = item.Name
-            });
-        }
-        catch (Exception ex)
-        {
-            _logger.LogError(ex, "Error logging material for job {JobId}", req.JobId);
-            return Json(new { success = false, message = "An error occurred. Please try again." });
-        }
-    }
+    // LogMaterial has been consolidated into InventoryController.LogMaterial.
 
     /// <summary>
     /// Inline-edits description, quantity, and unit price on a single job line item.
@@ -4554,14 +4486,6 @@ public class PatchJobItemRequest
     public decimal Quantity    { get; set; }
     public decimal UnitPrice   { get; set; }
 }
-public class LogMaterialRequest
-{
-    public int     JobId           { get; set; }
-    public int     InventoryItemId { get; set; }
-    public decimal QuantityUsed    { get; set; }
-    public string  TransactionType { get; set; } = "JobUsage";
-    public string? Notes           { get; set; }
-}
 public class CreateReworkJobRequest
 {
     public int ReworkRecordId { get; set; }