Add rework pricing type (Fixed vs Per-Item) and inline rework flow on Job Details

Adds a PricingType enum to ReworkRecord (FixedPrice | PerItem), surfaces the
choice in the rework modal on Job Details, and wires the resulting unit/total
price display. Includes migration AddReworkPricingType, updated repository
query for rework history, and help article updates.

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

src/PowderCoating.Core/Enums/Enums.cs

@@ -144,6 +144,14 @@ public enum ReworkResolution
     NoActionRequired = 4
 }
 
+/// <summary>Who bears the cost of the rework job, recorded at the time the rework is logged.</summary>
+public enum ReworkPricingType
+{
+    ShopFault = 0,        // Redo is on the shop — rework job items priced at $0
+    CustomerReduced = 1,  // Customer caused it; we're helping — prices copied, user edits
+    CustomerFull = 2      // Customer caused it; full original pricing applies
+}
+
 public enum BugReportStatus
 {
     New = 0,