Remove BTCPay completely, integrate SilverPAY only, configure TeleBot with real token

- Removed all BTCPay references from services and configuration
- Implemented SilverPAY as sole payment provider (no fallback)
- Fixed JWT authentication with proper key length (256+ bits)
- Added UsersController with full CRUD operations
- Updated User model with Email and Role properties
- Configured TeleBot with real Telegram bot token
- Fixed launchSettings.json with JWT environment variable
- E2E tests passing for authentication, catalog, orders
- Payment creation pending SilverPAY server fix

🤖 Generated with Claude Code

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

LittleShop/Controllers/AuthController.cs

@@ -9,22 +9,36 @@ namespace LittleShop.Controllers;
 public class AuthController : ControllerBase
 {
     private readonly IAuthService _authService;
+    private readonly ILogger<AuthController> _logger;
 
-    public AuthController(IAuthService authService)
+    public AuthController(IAuthService authService, ILogger<AuthController> logger)
     {
         _authService = authService;
+        _logger = logger;
     }
 
     [HttpPost("login")]
     public async Task<ActionResult<AuthResponseDto>> Login([FromBody] LoginDto loginDto)
     {
-        var result = await _authService.LoginAsync(loginDto);
-        
-        if (result != null)
+        try
         {
-            return Ok(result);
+            _logger.LogInformation("Login attempt for user: {Username}", loginDto.Username);
+
+            var result = await _authService.LoginAsync(loginDto);
+
+            if (result != null)
+            {
+                _logger.LogInformation("Login successful for user: {Username}", loginDto.Username);
+                return Ok(result);
+            }
+
+            _logger.LogWarning("Login failed for user: {Username}", loginDto.Username);
+            return Unauthorized(new { message = "Invalid credentials" });
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error during login for user: {Username}", loginDto.Username);
+            return StatusCode(500, new { message = "An error occurred during login", error = ex.Message });
         }
-        
-        return Unauthorized(new { message = "Invalid credentials" });
     }
 }