Add Timeclock settings tab in Company Settings with multi-kiosk support

Settings tab (Company Settings > Timeclock):
- Enable/disable timeclock toggle (hides nav link and attendance report when off)
- Allow multiple clock-ins per day toggle
- Auto clock-out after X hours (auto-closes forgotten open entries on next punch)
- Kiosk devices table: lists activated tablets with name, activated date, last seen;
  Deactivate button removes that device's access immediately

Multi-kiosk support (replaces single TimeclockKioskToken on Company):
- New TimeclockKioskDevice entity (one row per tablet, unique token, DeviceName, LastSeenAt)
- KioskActivate GET shows a form for optional device name before activating
- KioskDeactivate POST accepts device ID, deletes specific row (not all devices)
- Kiosk validation (Kiosk, KioskEmployees, KioskPunch) queries device table with
  ignoreQueryFilters since no user is logged in on kiosk requests
- LastSeenAt updated on each Kiosk page load

Enforcement:
- ClockIn and KioskPunch both auto-close stale entries if AutoClockOutHours is set
- ClockIn and KioskPunch both block second same-day punch if AllowMultiplePunches=false
- TimeclockEnabled=false hides nav link (SubscriptionMiddleware sets Items key) and
  returns Forbid on kiosk punch
- Migration: AddTimeclockSettings (adds 3 columns to Companies, new TimeclockKioskDevices table)

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

src/PowderCoating.Core/Interfaces/IUnitOfWork.cs

@@ -160,6 +160,7 @@ IRepository<ReworkRecord> ReworkRecords { get; }
 
     // Employee Timeclock
     IRepository<EmployeeClockEntry> EmployeeClockEntries { get; }
+    IRepository<TimeclockKioskDevice> TimeclockKioskDevices { get; }
 
     Task<int> SaveChangesAsync();
     Task<int> CompleteAsync(); // Alias for SaveChangesAsync