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_authenticate_byID.sql

@@ -0,0 +1,34 @@
+
+
+
+-- =============================================
+-- Author:		<Author,,Name>
+-- Create date: <Create Date, ,>
+-- Description:	<Description, ,>
+-- =============================================
+CREATE FUNCTION [dbo].[fis_admin_authenticate_byID]
+(
+	@useraccount_id varchar(10),
+	@password nvarchar(20)
+)
+RETURNS @RET TABLE ( [useraccount_id] varchar(5), [auth] smallint, [name] nvarchar(100) null, [firstname] nvarchar(100) null, [email] varchar(255) NULL, [mobile] varchar(50) null, [functions] varchar(1000), [language] varchar(2), [fullname] nvarchar(255) null, [fullname_rev] nvarchar(255) null)
+AS
+BEGIN
+	DECLARE @auth smallint = -1;
+	DECLARE @name nvarchar(255), @mobile varchar(50), @functions varchar(1000) = '';
+
+	IF EXISTS( SELECT 0
+		FROM [dbo].[fis_useraccounts] as ua
+		WHERE ua.[DateDeleted] is null AND ua.[DateDisabled] is null
+			AND [useraccount_id] = @useraccount_id and ISNULL(@useraccount_id, '') <> ''
+			AND CAST(DECRYPTBYKEY(ua.[password_enc]) as nvarchar(20)) = @password
+			AND @password <> ''
+			AND ua.[password_enc] is not null
+		)
+	BEGIN
+		INSERT INTO @RET SELECT * FROM [dbo].[fis_admin_getUserAccount](@useraccount_id);
+	END
+
+	RETURN;
+
+END