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_getUserName_rev.sql

@@ -0,0 +1,28 @@
+
+
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date, ,>
+-- Description:	<Description, ,>
+-- =============================================
+CREATE FUNCTION [dbo].[fis_admin_getUserName_rev]
+(
+	@name_enc varbinary(260)
+	,@firstname_enc varbinary(260)
+	,@title_enc varbinary(50)
+)
+RETURNS nvarchar(255)
+AS
+BEGIN
+	DECLARE @Username nvarchar(255);
+
+	SET @Username = CAST(	
+											ISNULL(CASE WHEN @name_enc is null THEN '' ELSE CAST(DECRYPTBYKEY(@name_enc ) as nvarchar(100)) END, '')
+											+ N', ' + ISNULL(CASE WHEN @firstname_enc is null THEN '' ELSE CAST(DECRYPTBYKEY(@firstname_enc) as nvarchar(100)) + ' ' END,'')
+											
+									as nvarchar(255))
+
+
+	RETURN @username;
+
+END