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/ott_csv_contains.sql

@@ -0,0 +1,30 @@
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date, ,>
+-- Description:	<Description, ,>
+-- =============================================
+CREATE FUNCTION [dbo].[ott_csv_contains]
+(
+	@text varchar(500)
+	,@fragment varchar(500)
+)
+RETURNS bit
+AS
+BEGIN
+	DECLARE @RET bit;
+
+	IF ISNULL(@text, '') = '' OR ISNULL(@fragment, '') = ''
+		SET @REt = 0;
+	ELSE
+		BEGIN
+			-- Will be true 
+			-- if any of the fragments exist in the list of text-items
+
+			WITH texts as (SELECT * FROM string_split(ISNULL(@text,''), ','))
+				,fragments as (SELECT * FROM string_split(ISNULL(@fragment,''), ','))
+			SELECT @RET = CASE WHEN EXISTS (SELECT * FROM texts JOIN fragments ON texts.[value] = fragments.[value]) THEN 1 ELSE 0 END;
+		END;
+
+	RETURN @RET;
+
+END