style(backend): apply dotnet format whitespace normalization

- Applied dotnet format to 24 files in backend/
- Corrects spacing, indentation, and formatting consistency
- No functional changes to code logic

Ultraworked with Sisyphus <https://github.com/code-yeongyu/oh-my-opencode>
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/WorkClub.Api/Services/ShiftService.cs

@@ -57,7 +57,7 @@ public class ShiftService
     public async Task<ShiftDetailDto?> GetShiftByIdAsync(Guid id)
     {
         var shift = await _context.Shifts.FindAsync(id);
-        
+
         if (shift == null)
             return null;
 
@@ -91,7 +91,7 @@ public class ShiftService
     public async Task<(ShiftDetailDto? shift, string? error)> CreateShiftAsync(CreateShiftRequest request, Guid createdById)
     {
         var tenantId = _tenantProvider.GetTenantId();
-        
+
         var shift = new Shift
         {
             Id = Guid.NewGuid(),
@@ -132,7 +132,7 @@ public class ShiftService
     public async Task<(ShiftDetailDto? shift, string? error, bool isConflict)> UpdateShiftAsync(Guid id, UpdateShiftRequest request)
     {
         var shift = await _context.Shifts.FindAsync(id);
-        
+
         if (shift == null)
             return (null, "Shift not found", false);
 
@@ -197,7 +197,7 @@ public class ShiftService
     public async Task<bool> DeleteShiftAsync(Guid id)
     {
         var shift = await _context.Shifts.FindAsync(id);
-        
+
         if (shift == null)
             return false;
 
@@ -212,7 +212,7 @@ public class ShiftService
         var tenantId = _tenantProvider.GetTenantId();
 
         var shift = await _context.Shifts.FindAsync(shiftId);
-        
+
         if (shift == null)
             return (false, "Shift not found", false);