fix: increase root_event size to 64KiB

[forestileao]

Summary

Increase the shared event payload size limit from 32 KiB to 64 KiB.

This fixes webhook requests that were failing with 500 when the emitted root event payload was larger than the previous global cap, including larger GitHub pull_request webhook payloads.

Changes

• Updated DefaultMaxPayloadSize in pkg/workers/contexts/common.go
  • from 32 * 1024
  • to 64 * 1024

Why

Root event emission uses the shared payload size limit enforced by EventContext and ExecutionStateContext.

Some webhook payloads, especially GitHub PR events, can exceed 32 KiB. When that happened, event persistence returned event payload too large, which bubbled up as a 500 from the webhook endpoint.

Raising the limit to 64 KiB keeps the fix simple and avoids the broader jump to 256 KiB.

[superplanehq-integration]

👋 Commands for maintainers:

• /sp start - Start an ephemeral machine (takes ~30s)
• /sp stop - Stop a running machine (auto-executed on pr close)

[forestileao]

👍