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__createInvoice_ServiceRequest.sql

@@ -0,0 +1,29 @@
+CREATE   PROCEDURE [dbo].[fds__createInvoice_ServiceRequest]
+	@InvId varchar(10)
+	,@mfr__servicerequest bigint
+	,@title nvarchar(max)
+	,@value_net numeric(10,3)
+	,@SortOrder tinyint
+AS
+BEGIN
+	SET NOCOUNT ON;
+
+	DECLARE @InvRqId varchar(10) = [dbo].[fds__fn_invoice-srq_id]();
+
+    INSERT INTO [dbo].[fds__invoice_servicerequests]
+           ([Id]
+		   ,[InvId]
+           ,[mfr__servicerequest]
+		   ,[title]
+           ,[value_net]
+           ,[SortOrder])
+	OUTPUT inserted.*
+     VALUES
+           (@InvRqId
+		   ,@InvId
+           ,@mfr__servicerequest
+		   ,@title
+           ,@value_net
+           ,@SortOrder);
+
+END