v4.9.0-rc2

feat: lake: reliably cache logs and hashes (#4402)

Moves the cached log into the trace file (no more `.log.json`). This
means logs are no longer cached on fatal errors and this ensures that an
out-of-date log is not associated with an up-to-date trace. Separately,
`.hash` file generation was changed to be more reliable as well. `.hash`
files are deleted as part of the build and always regenerate with
`--rehash`.

Closes #2751.

(cherry picked from commit db74ee9e83c631dd4bab9b7b6a10d0793cb0cbef)