feat: Enhance error logging for PDF preview failures and SQL timeouts

- Implemented a new method `ShapeTableNames` to gather entity and navigation table names, ensuring no blanks or duplicates are included.
- Updated `FdsMfrClient` to handle cases where schema queries return no tables, logging appropriate warnings and preventing misleading errors.
- Introduced `PdfPreviewAsync` in `IntranetController` to manage PDF preview rendering, capturing detailed logs for failures and notifying users with readable error messages.
- Added comprehensive unit tests for error logging and table name shaping to ensure robustness and correctness.
- Documented decision to persist user action failures to the `fds__admin_logdebug` table, enhancing support diagnostics.

Fuchs_DataService/Fuchs_DataService.xml

@@ -16,6 +16,12 @@
         <member name="F:fds.FdsMfr.InvoiceFileDownloadConcurrency">
             <summary>Max parallel invoice-file downloads (independent per file).</summary>
         </member>
+        <member name="M:fds.FdsMfrClient.DatabaseSchema.ShapeTableNames(System.String,System.Data.DataRowCollection)">
+            <summary>
+            Entity table plus its navigation tables, without blanks: the list of tables whose
+            (empty) shape is loaded. Empty when the entity table itself is unknown.
+            </summary>
+        </member>
         <member name="T:fds.FdsConfig">
             <summary>
             Holds the application <see cref="T:Microsoft.Extensions.Configuration.IConfiguration"/> supplied by the host (the Fuchs web app).