## Context
`posthog-cli` sourcemap upload fails with `operation timed out` at `bulk_start_upload` for Next.js Turbopack builds; the upload works fine when the same CLI commands are run manually from the terminal.

## Verified resolution
Maintainer daibhin root-caused it: the Next.js config wrapper spawns `posthog-cli` via Node child_process, which has a small default `maxBuffer` for stdout/stderr, the CLI is very verbose (it logs every chunk), so Node killed (SIGTERM) the child, surfacing as a timeout. Fix: increase `maxBuffer` (e.g. 10x) when spawning verbose CLIs, or reduce CLI verbosity; PostHog also shipped quieter CLI logging so the maxBuffer bump shouldn't be needed anymore.