fix(release): stage PGO blob through --rawfile to avoid ARG_MAX (#2421)
## Summary
The `Commit and tag via GitHub API` step in `release.yaml` blew up on
its first real dispatch
(https://github.com/php/frankenphp/actions/runs/25914409401):
```
/usr/bin/jq: Argument list too long
gh: Validation Failed (HTTP 422)
```
`jq --arg content "$(base64 -w0 <default.pgo)" ...` was passing the ~2
MB base64-encoded PGO blob as a CLI argument, which exceeds the runner's
`ARG_MAX`.
Fix: stage the base64 in a tmpfile and feed it via `--rawfile` so jq
reads it from disk, not the argv. `go.mod` and `go.sum` keep going
through `--rawfile` for consistency.
This needs to land before the next release dispatch can succeed.