feat: Enhance invoice file backup procedure to include JSON snapshots

- Updated the stored procedure `fds__admin_backupAndClearInvoiceFile.sql` to back up not only the invoice file but also JSON snapshots of related data (invoices, items, details, service requests) to ensure consistency and traceability.
- Modified the table structure of `fds__invoice_file_backups` to accommodate new JSON columns for storing these snapshots.
- Added an ADR (0030) document to outline the decision and rationale behind these changes, emphasizing the importance of maintaining a consistent set of data alongside the backed-up file.

Fuchs_Database/dbo/Stored Procedures/fds__admin_backupAndClearInvoiceFile.sql

@@ -8,7 +8,10 @@
 --              admin/backupclearinvoicefile action (fds_sys > 4 gate, IntranetController.Admin.cs),
 --              which logs through the normal ILogger/DB-log-sink pipeline (ADR 0024) instead.
 --
---              Copies the invoice's current [file] bytes into [dbo].[fds__invoice_file_backups],
+--              Copies the invoice's current [file] bytes into [dbo].[fds__invoice_file_backups]
+--              together with JSON snapshots of its fds__invoices / fds__invoice_items /
+--              fds__invoice_details / fds__invoice_servicerequests rows (ADR 0030: file + data
+--              as one consistent set),
 --              then clears [file] so the document regenerates on next read (ADR 0025). Both steps
 --              run in one transaction. Only a finalised, non-external invoice qualifies — the same
 --              precondition ADR 0025 puts on regeneration: clearing a draft's file would let the
@@ -37,11 +40,42 @@ BEGIN
 	BEGIN TRY
 	BEGIN TRANSACTION;
 
-	INSERT INTO [dbo].[fds__invoice_file_backups] ([InvoiceId], [DocumentName], [file], [BackedUpBy])
-		SELECT [Id], [DocumentName], [file], @authuser
-		FROM [dbo].[fds__invoices]
-		WHERE [Id] = @Id AND [file] IS NOT NULL
-		  AND [DateFinalized] IS NOT NULL AND ISNULL([IsExternal], 0) = 0;
+	-- The backup row carries the file AND JSON snapshots of the data rows it was rendered from
+	-- (ADR 0030), so a backup is a self-contained, consistent set. The invoice snapshot lists
+	-- its columns explicitly to leave [file] out (it is already stored as bytes in [file] and
+	-- would otherwise be base64-duplicated into the JSON); items, details and service requests take
+	-- every column.
+	INSERT INTO [dbo].[fds__invoice_file_backups]
+		([InvoiceId], [DocumentName], [file], [InvoiceJson], [InvoiceItemsJson], [InvoiceDetailsJson],
+		 [InvoiceServiceRequestsJson], [BackedUpBy])
+		SELECT i.[Id], i.[DocumentName], i.[file],
+			(SELECT i.[Id], i.[Version], i.[InvoiceId], i.[InvoiceType], i.[InvoiceTitle], i.[DocumentName],
+					i.[InvoiceBalance], i.[InvoiceBalance_net], i.[InvoiceVAT_net1], i.[InvoiceVAT_1],
+					i.[InvoiceVAT_net2], i.[InvoiceVAT_2], i.[PaymentTerm], i.[DueDate], i.[CustomerId],
+					i.[SendToAddress], i.[SendToEmail], i.[SendToEmailCc], i.[ProvisionPeriod], i.[ProvisionLocation],
+					i.[PaymentStatus], i.[IsPayed], i.[IsSent], i.[IsFinal], i.[IsCanceled], i.[Replaces_InvId],
+					i.[CustomValues], i.[SendToAddressJson], i.[DateSent], i.[UserSent], i.[DateFinalized], i.[UserFinalized],
+					i.[DateCancelled], i.[UserCancelled], i.[DateCreated], i.[UserCreated], i.[DateModified], i.[UserModified],
+					i.[ExternalId], i.[IsExternal], i.[file_guid]
+			 FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER),
+			(SELECT it.*
+			 FROM [dbo].[fds__invoice_items] it
+			 WHERE it.[InvId] = i.[Id]
+			 ORDER BY it.[SortOrder], it.[Position], it.[Id]
+			 FOR JSON PATH, INCLUDE_NULL_VALUES),
+			(SELECT d.*
+			 FROM [dbo].[fds__invoice_details] d
+			 WHERE d.[InvId] = i.[Id]
+			 FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER),
+			(SELECT sr.*
+			 FROM [dbo].[fds__invoice_servicerequests] sr
+			 WHERE sr.[InvId] = i.[Id]
+			 ORDER BY sr.[SortOrder], sr.[Id]
+			 FOR JSON PATH, INCLUDE_NULL_VALUES),
+			@authuser
+		FROM [dbo].[fds__invoices] i
+		WHERE i.[Id] = @Id AND i.[file] IS NOT NULL
+		  AND i.[DateFinalized] IS NOT NULL AND ISNULL(i.[IsExternal], 0) = 0;
 
 	UPDATE [dbo].[fds__invoices]
 		SET [file] = NULL

Fuchs_Database/dbo/Tables/fds__invoice_file_backups.sql

@@ -3,6 +3,15 @@ CREATE TABLE [dbo].[fds__invoice_file_backups] (
     [InvoiceId]    VARCHAR (10)    NOT NULL,
     [DocumentName] VARCHAR (50)    NULL,
     [file]         VARBINARY (MAX) NOT NULL,
+    -- JSON snapshots (FOR JSON PATH) of the invoice's data rows at backup time, so the file and
+    -- the data it was rendered from stay together as one consistent set (ADR 0030).
+    -- InvoiceJson: the fds__invoices row without [file]; InvoiceItemsJson: array of
+    -- fds__invoice_items rows; InvoiceDetailsJson: the fds__invoice_details row (NULL if none);
+    -- InvoiceServiceRequestsJson: array of fds__invoice_servicerequests rows.
+    [InvoiceJson]                NVARCHAR (MAX) NULL,
+    [InvoiceItemsJson]           NVARCHAR (MAX) NULL,
+    [InvoiceDetailsJson]         NVARCHAR (MAX) NULL,
+    [InvoiceServiceRequestsJson] NVARCHAR (MAX) NULL,
     [BackedUpAt]   DATETIME        CONSTRAINT [DF_fds__invoice_file_backups_BackedUpAt] DEFAULT (getutcdate()) NOT NULL,
     [BackedUpBy]   VARCHAR (25)    NULL,
     CONSTRAINT [PK_fds__invoice_file_backups] PRIMARY KEY CLUSTERED ([uid] ASC)