Fix auth, Bootstrap, Blazor nav, LDAP, and deployment pipeline for working Central UI

Bootstrap served locally with absolute paths and <base href="/">.
LDAP auth uses search-then-bind with service account for GLAuth compatibility.
CookieAuthenticationStateProvider reads HttpContext.User instead of parsing JWT.
Login/logout forms opt out of Blazor enhanced nav (data-enhance="false").
Nav links use absolute paths; seed data includes Design/Deployment group mappings.
DataConnections page loads all connections (not just site-assigned).
Site appsettings configured for Test Plant A; Site registers with Central on startup.
DeploymentService resolves string site identifier for Akka routing.
Instances page gains Create Instance form.

src/ScadaLink.Commons/Interfaces/Repositories/ISiteRepository.cs

@@ -18,6 +18,7 @@ public interface ISiteRepository
 
     // Data Connections
     Task<DataConnection?> GetDataConnectionByIdAsync(int id, CancellationToken cancellationToken = default);
+    Task<IReadOnlyList<DataConnection>> GetAllDataConnectionsAsync(CancellationToken cancellationToken = default);
     Task<IReadOnlyList<DataConnection>> GetDataConnectionsBySiteIdAsync(int siteId, CancellationToken cancellationToken = default);
     Task AddDataConnectionAsync(DataConnection connection, CancellationToken cancellationToken = default);
     Task UpdateDataConnectionAsync(DataConnection connection, CancellationToken cancellationToken = default);