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__setReportVAT.sql

@@ -0,0 +1,27 @@
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date,,>
+-- Description:	<Description,,>
+-- =============================================
+CREATE PROCEDURE [dbo].[fds__setReportVAT]
+	@id bigint
+	,@entitytype varchar(50)
+	,@vat numeric(5,2)
+	,@authuser varchar(100)
+AS
+BEGIN
+	SET NOCOUNT ON;
+
+
+	MERGE [dbo].[fds__custom_vat] as TARGET
+		USING (VALUES(@entitytype, @id, @vat)) as SOURCE ([EntityType],[EntityID],[VAT])
+		ON TARGET.[EntityType] = SOURCE.[EntityType] AND TARGET.[EntityID] = SOURCE.[EntityID]
+	WHEN MATCHED THEN
+		UPDATE SET 
+			[VAT] = SOURCE.[VAT]
+	WHEN NOT MATCHED THEN
+		INSERT ([EntityType],[EntityID],[VAT])
+		VALUES (SOURCE.[EntityType],SOURCE.[EntityID],SOURCE.[VAT])
+	;
+    
+END