Added new navigation menu items in `_Layout.cshtml` for "Rechnungen" (Invoices) and "PDF hochladen" (Upload PDF) with icons, paths, and selection logic.
Created a new Razor Page `Index.cshtml` to display imported invoices using a `DataGrid` with features like filtering, paging, and column formatting. Added a conditional message for when no invoices are available.
Implemented the `IndexModel` class in `Index.cshtml.cs` to handle backend logic, including fetching and sorting invoices from the database using `AppDbContext`.
Enhanced `ZugferdInvoice` model with default string values to prevent nulls. Updated `Upload.cshtml` to display parsed invoice data.
Refactored `Upload.cshtml.cs` to handle ZUGFeRD XML parsing and database storage. Introduced `ImportedInvoice` property and buffered file processing with `MemoryStream`.
Extended `ZugferdParserService` to support ZUGFeRD v1, v1.0 FeRD, and v2/Factur-X. Added version-specific parsing methods and namespaces. Improved date and decimal parsing for robustness.
Added database migration (`20260522084606_InitialCreate`) to define `ZugferdInvoices` table. Updated migration snapshot to reflect schema changes.
Fixed localization issue in `Upload.cshtml.cs` error message.
The `ConnectionStrings` section in the `appsettings.json` file was updated. The `EcmContext` connection string, previously an empty string, was replaced with a connection string pointing to a SQL Server instance.
The new connection string includes the server name, database name, user ID, password, and a flag to trust the server certificate. This change enables the application to connect to the specified SQL Server database.
