feat: Convert website from static HTML to .NET 9.0 Blazor Web App

Major architectural upgrade from static HTML site to modern Blazor Web App:

- Migrated to .NET 9.0 Blazor Web App framework
- Converted home page with 4 gateway cards (Help Desk, App Store, Cloud, SDK)
- Added new SDK card linking to comprehensive SDK documentation
- Converted SDK documentation page to Blazor component
- Updated template download links to nuget.silverlabs.uk repository
- Implemented multi-stage Docker build with .NET SDK 9.0
- Created Blazor-optimized nginx configuration
- Preserved all original styling and animations
- Added .gitignore for Blazor build artifacts

Technical changes:
- New BlazorApp/ project structure with Components architecture
- MainLayout simplified (no default navigation)
- CSS ported to wwwroot (styles.css + sdk-styles.css)
- Multi-stage Dockerfile: Build with dotnet SDK, serve with nginx
- GitLab CI/CD pipeline compatible (auto-detects new Dockerfile)

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

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

BlazorApp/Properties/launchSettings.json

@@ -0,0 +1,23 @@
+{
+  "$schema": "https://json.schemastore.org/launchsettings.json",
+    "profiles": {
+      "http": {
+        "commandName": "Project",
+        "dotnetRunMessages": true,
+        "launchBrowser": true,
+        "applicationUrl": "http://localhost:5072",
+        "environmentVariables": {
+          "ASPNETCORE_ENVIRONMENT": "Development"
+        }
+      },
+      "https": {
+        "commandName": "Project",
+        "dotnetRunMessages": true,
+        "launchBrowser": true,
+        "applicationUrl": "https://localhost:7104;http://localhost:5072",
+        "environmentVariables": {
+          "ASPNETCORE_ENVIRONMENT": "Development"
+        }
+      }
+    }
+  }