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_combineAddress.sql

@@ -0,0 +1,27 @@
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date, ,>
+-- Description:	<Description, ,>
+-- =============================================
+CREATE FUNCTION [dbo].[fds__fn_combineAddress]
+(
+	@AddressString nvarchar(255)
+	,@AddressString2 nvarchar(255)
+	,@AddressString3 nvarchar(255)
+	,@Postal nvarchar(255)
+	,@City nvarchar(255)
+	,@State nvarchar(255)
+	,@Country nvarchar(255)
+)
+RETURNS nvarchar(1000)
+AS
+BEGIN
+	DECLARE @address nvarchar(1000) = STUFF(   (SELECT (CHAR(10) + [t]) as [text()] FROM 
+													(SELECT * FROM (VALUES(@AddressString), (@AddressString2), (@AddressString3), (LTRIM(RTRIM(ISNULL(@postal, '') + ' ' + ISNULL(@city, '')))), (@state), (@country)) z ([t]) WHERE ISNULL([t], '') <> '')y
+													FOR XML PATH
+												, TYPE).value('.[1]','nvarchar(1000)')
+											, 1, 1, '');
+												
+	RETURN @address;
+
+END