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/Functions/fds__fn_InvoiceIDs_mfr.sql

@@ -0,0 +1,30 @@
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date, ,>
+-- Description:	<Description, ,>
+-- =============================================
+CREATE FUNCTION [dbo].[fds__fn_InvoiceIDs_mfr]
+(
+	@invoiceid varchar(255),
+	@other varchar(1000)
+)
+RETURNS varchar(1000)
+AS
+BEGIN
+	DECLARE @RET varchar(1000) = REPLACE(LTRIM(ISNULL(@invoiceid,'')),'Preview','');
+	
+	IF @RET <> ''
+		SET @RET = TRIM(REPLACE(@RET, '  ', ' '));
+
+	IF @RET <> ''
+		SET @RET = REPLACE(@RET, ' ',' (mfr)' + CHAR(10)) + ' (mfr)';
+
+	IF @RET <> '' AND ISNULL(@other, '') <> ''
+		SET @RET = @RET + CHAR(10);
+
+	SET @RET = @RET + ISNULL(@other, '');
+		
+	
+	RETURN @RET;
+
+END