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/Stored Procedures/fds__setInvoicePayed.sql

@@ -0,0 +1,25 @@
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date,,>
+-- Description:	<Description,,>
+-- =============================================
+CREATE PROCEDURE [dbo].[fds__setInvoicePayed]
+	@Id varchar(15),
+	@authuser varchar(25)
+AS
+BEGIN
+	SET NOCOUNT ON;
+	DECLARE @now datetime = GETUTCDATE();
+
+	IF [dbo].[fis_getModuleAuth]('fds_inv', @authuser) < 2
+		THROW 60000, N'not authorized', 1;  
+	
+	INSERT INTO [dbo].[fds__admin_activity] ([activity] ,[authuser] ,[info])
+		VALUES ('fds__setInvoicePayed' ,@authuser , (SELECT * FROM (VALUES(@Id, @authuser)) as z ([id],[authuser]) FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER));
+
+    UPDATE [dbo].[fds__invoices] SET [IsPayed] = 1, [paymentstatus] = 'm', [DateModified] = @now, [UserModified] = @authuser, [version] = (ISNULL([version],0) + 1)
+	OUTPUT inserted.*
+		WHERE [Id] = @Id AND @Id is not null and [IsPayed] = 0;
+
+
+END