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/fis_admin_getUserSetting.sql

@@ -0,0 +1,26 @@
+
+
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date, ,>
+-- Description:	<Description, ,>
+-- =============================================
+CREATE FUNCTION [dbo].[fis_admin_getUserSetting]
+(
+	@useraccount_id varchar(5)
+	, @key varchar(25)
+)
+RETURNS varchar(255)
+AS
+BEGIN
+	DECLARE @ret varchar(25);
+
+	SET @ret =	 ISNULL((SELECT TOP(1) 
+							ISNULL((SELECT TOP(1) [value] FROM [fis_useraccounts_settings] as s WHERE s.[useraccount_id] = ua.[useraccount_id] and s.[key] = @key), '')
+						FROM [dbo].[fis_useraccounts] as ua
+						WHERE ua.[DateDeleted] is null
+							AND ua.[useraccount_id] = @useraccount_id), '');
+
+	RETURN ISNULL(@ret,'');
+
+END