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/Interfaces/Repositories/IJobRepository.cs

@@ -92,4 +92,10 @@ public interface IJobRepository : IRepository<Job>
     /// were never completed and rolled past their scheduled day.
     /// </summary>
     Task<List<Job>> GetOverdueScheduledJobsAsync();
+
+    /// <summary>
+    /// Returns the count of rework jobs linked to <paramref name="originalJobId"/>
+    /// (including soft-deleted) so the next rework suffix (R1, R2, …) can be determined.
+    /// </summary>
+    Task<int> GetReworkJobCountAsync(int originalJobId);
 }