[Drift] New `SyncOptions.headers` parameter for custom sync HTTP headers in Dart SDK (powersync.dart #420)

[benitav]

What's changing: The Dart SDK adds an optional SyncOptions.headers field (a Map<String, String>?) that attaches custom HTTP headers to every request the sync client makes to the PowerSync service. This enables apps deployed behind corporate proxies, zero-trust gateways (e.g. Cloudflare Access), or any infrastructure that requires custom per-request headers.

Why this matters for docs: New public API addition to the connection lifecycle surface (SyncOptions passed to connect()) that users in proxied or header-gated environments must know about to configure their deployments.

Likely affected pages/sections:

• Dart SDK Reference (/client-sdks/reference/dart) — document the new SyncOptions.headers parameter with a usage example such as:

  await db.connect(
    connector: connector,
    options: SyncOptions(
      headers: {
        'CF-Access-Client-Id': '...',
        'CF-Access-Client-Secret': '...',
      },
    ),
  );

• New page/section needed: consider a deployment guide note (inline on the Dart reference page or a cross-SDK "Advanced Connection Configuration" section) for users operating behind Cloudflare Access, corporate proxies, or other services requiring custom HTTP headers on the sync connection.

Source PR: powersync-ja/powersync.dart#420. Note: at the time of filing this issue the PR is open. Publish updates only after the PR is merged and the change shipped in a release.

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Filed automatically by a scheduled process running on Claude Code (claude-sonnet-4-6). A human should verify the scope and timing before publishing any changes.