[Drift] Offline-first file attachments helper added to .NET SDK (powersync-dotnet #68)

[benitav]

What shipped: A new offline-first file attachments helper has been added to PowerSync.Common for .NET. It includes AttachmentQueue (lifecycle orchestration: upload/download/delete/archive), SyncingService (throttled sync loop with connectivity detection), FileManagerLocalStorage (cross-platform local file adapter using System.IO.File), and IAttachmentErrorHandler (extensible retry/archive error handling). The Attachment type maps to PowerSync's schema via existing [Table] and [Column] attributes.

Why this needs docs: New major feature — the .NET SDK now has parity with other SDKs for file attachment sync, and users need guidance on how to configure and use the AttachmentQueue, define the watchAttachments query, and implement storage adapters.

Likely affected pages/sections:

• .NET SDK documentation — add a new "File Attachments" page covering: schema setup using Attachment, wiring up AttachmentQueue, implementing watchAttachments, configuring local storage (FileManagerLocalStorage) and remote storage adapters, and customising error handling via IAttachmentErrorHandler
• PowerSync attachments overview / feature comparison page — add .NET to the list of SDKs that support file attachments
• Getting started with .NET — mention attachments as an available feature

Source PR: powersync-ja/powersync-dotnet#68

CC: @benitav @austinbhale

[benitav]

Hey Austin, sorry that our bot pinged you here. Feel free to ignore this for now - we can own updating the docs once we're closer to a release, unless you would like to!