Add Employee Timeclock feature with kiosk, attendance report, and payroll CSV export

- New EmployeeClockEntry entity (facility-level attendance, separate from job time entries)
- KioskPin added to ApplicationUser; TimeclockKioskToken added to Company
- TimeclockController: clock in/out, who's in, 14-day history, manager edit/delete,
  tablet kiosk with device-cookie auth, PIN management via Users edit page
- Kiosk UI: employee tile grid + 4-digit PIN pad + auto-detect clock-in vs clock-out
- Attendance report at /Reports/Attendance with weekly subtotal rows
- Payroll CSV export at /Reports/AttendanceCsv (flat, one row per segment)
- AllowCustomFormulas wired through PlatformSubscriptionController + subscription views
- Fix soft-delete bug on CustomItemTemplate (missing HasQueryFilter in OnModelCreating)
- Help article (Help/Timeclock.cshtml) and AI knowledge base updated
- Migrations: AddEmployeeTimeclock, AddTimeclockKioskToken

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

src/PowderCoating.Infrastructure/Repositories/UnitOfWork.cs

@@ -123,6 +123,9 @@ public class UnitOfWork : IUnitOfWork
     // Customer Intake Kiosk
     private IRepository<KioskSession>? _kioskSessions;
 
+    // Employee Timeclock
+    private IRepository<EmployeeClockEntry>? _employeeClockEntries;
+
     // Custom Formula Templates
     private IRepository<CustomItemTemplate>? _customItemTemplates;
 
@@ -460,6 +463,10 @@ public class UnitOfWork : IUnitOfWork
     public IRepository<KioskSession> KioskSessions =>
         _kioskSessions ??= new Repository<KioskSession>(_context);
 
+    /// <summary>Repository for <see cref="EmployeeClockEntry"/> facility-level clock-in/clock-out records; tenant-filtered with soft delete. Multiple entries per day are fully supported.</summary>
+    public IRepository<EmployeeClockEntry> EmployeeClockEntries =>
+        _employeeClockEntries ??= new Repository<EmployeeClockEntry>(_context);
+
     /// <summary>Repository for <see cref="CustomItemTemplate"/> per-company reusable NCalc pricing formula templates; tenant-filtered with soft delete.</summary>
     public IRepository<CustomItemTemplate> CustomItemTemplates =>
         _customItemTemplates ??= new Repository<CustomItemTemplate>(_context);