Add Fuchs_Database SSDT project (schema source of truth)

Adds the SQL Server Data Tools project for the fuchs_fds database — tables,
table types, functions and stored procedures that the backend calls (e.g.
fds__getInvoice, fds__merge_bankingtransactions, fds__tt__bankingtransactions,
fds__admin_getReportCatalog, fis_* auth). Build/model caches (bin, obj,
*.dbmdl, *.jfm, *.user) are git-ignored.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Fuchs_Database/dbo/Stored Procedures/fds__toggleRequestHidden.sql

@@ -0,0 +1,28 @@
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date,,>
+-- Description:	<Description,,>
+-- =============================================
+CREATE PROCEDURE [dbo].[fds__toggleRequestHidden]
+	@Id bigint,
+	@authuser varchar(25)
+AS
+BEGIN
+	SET NOCOUNT ON;
+
+	MERGE [dbo].[fds__custom_servicerequest] as TARGET
+		USING (SELECT [id] FROM [mfr__servicerequests] as sr where [id] = @id) as SOURCE ([id]) ON TARGET.[EntityId] = SOURCE.[Id]
+	WHEN MATCHED THEN
+		UPDATE SET 
+			[hidden] = CASE WHEN TARGET.[hidden] = 1 THEN 0 ELSE 1 END
+	WHEN NOT MATCHED BY TARGET THEN
+		INSERT
+			([EntityId]
+			 ,[hidden])
+		VALUES
+			(SOURCE.[Id]
+			 ,1)
+	OUTPUT 
+		inserted.*;
+
+END