feat: Display runtime connection string in dashboard

Added connection string display to System Information section of dashboard.

- Injected IConfiguration into DashboardController
- Added ConnectionString to ViewData
- Displayed in monospace code format for easy reading
- Shows actual runtime connection string from configuration
- Helps verify which database file is being used in different environments

This makes it easier to troubleshoot database location issues, especially
when deploying to different environments (Development, Production, CT109, etc.).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

LittleShop/Areas/Admin/Controllers/DashboardController.cs

@@ -11,15 +11,18 @@ public class DashboardController : Controller
     private readonly IOrderService _orderService;
     private readonly IProductService _productService;
     private readonly ICategoryService _categoryService;
+    private readonly IConfiguration _configuration;
 
     public DashboardController(
         IOrderService orderService,
         IProductService productService,
-        ICategoryService categoryService)
+        ICategoryService categoryService,
+        IConfiguration configuration)
     {
         _orderService = orderService;
         _productService = productService;
         _categoryService = categoryService;
+        _configuration = configuration;
     }
 
     public async Task<IActionResult> Index()
@@ -47,6 +50,9 @@ public class DashboardController : Controller
         ViewData["RecentOrders"] = orders.OrderByDescending(o => o.CreatedAt).Take(5);
         ViewData["TopProducts"] = products.OrderByDescending(p => p.StockQuantity).Take(5);
 
+        // System information
+        ViewData["ConnectionString"] = _configuration.GetConnectionString("DefaultConnection") ?? "Not configured";
+
         return View();
     }
 }

LittleShop/Areas/Admin/Views/Dashboard/Index.cshtml

@@ -228,6 +228,7 @@ else
                 <ul class="list-unstyled">
                     <li><strong>Framework:</strong> .NET 9.0</li>
                     <li><strong>Database:</strong> SQLite</li>
+                    <li><strong>Connection String:</strong> <code class="text-muted small">@ViewData["ConnectionString"]</code></li>
                     <li><strong>Authentication:</strong> Cookie-based</li>
                     <li><strong>Crypto Support:</strong> 8 currencies via BTCPay Server</li>
                     <li><strong>API Endpoints:</strong> Available for client integration</li>