Fix login accepting wrong credentials (empty user signed in anyway)

fis_admin_getUserAccount always inserted a result row, even when no
matching user was found, so fis_admin_authenticate never truly
returned "no result" on wrong credentials — the login handler then
signed the caller in with an empty useraccount_id. The authenticated
shell rendered (IsAuthenticated only checks the claim exists), while
every data endpoint 401'd (FuchsUserIdentity.IsAuthenticated also
checks the id is non-empty), producing an empty portal.

Also treat an empty useraccount_id in HandleLogin as a failed login
(defense in depth) and fix a column-name mismatch (auth vs
authorization) that was silently zeroing the authorization level.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Fuchs_Database/dbo/Functions/fis_admin_getUserAccount.sql

@@ -36,19 +36,22 @@ BEGIN
 						(SELECT ',' + [value] as [text()] FROM [fis_useraccounts_settings] WHERE [useraccount_id] = @useraccount_id and [key] = 'intranet_function' FOR XML PATH(''), TYPE).value('.','nvarchar(max)')
 					, 1,1,'');
 
-	INSERT INTO @RET 
-		VALUES( 
-				 @useraccount_id
-				,IIF(@useraccount_id is null, -1, @auth)
-				,IIF(@useraccount_id is null, null, @name)
-				,IIF(@useraccount_id is null, null, @firstname)
-				,IIF(@useraccount_id is null, null, @email)
-				,IIF(@useraccount_id is null, null, @mobile)
-				,IIF(@useraccount_id is null, null, @functions)
-				,IIF(@useraccount_id is null, null, @language)
-				,IIF(@useraccount_id is null, null, @fullname)
-				,IIF(@useraccount_id is null, null, @fullname_rev)
-			  );
+	IF @useraccount_id IS NOT NULL
+	BEGIN
+		INSERT INTO @RET
+			VALUES(
+					 @useraccount_id
+					,@auth
+					,@name
+					,@firstname
+					,@email
+					,@mobile
+					,@functions
+					,@language
+					,@fullname
+					,@fullname_rev
+				  );
+	END
 
 	RETURN;