A batch of small, self-contained fixes and docs/example additions.
Fixes#625 - align the example config's `force_pull` with the actual default (`false`)
Fixes#804 - return an error instead of discarding `os.UserHomeDir()` when defaulting `cache.dir`/`host.workdir_parent`
Fixes#571 - send a `gitea-runner/<version>` User-Agent on API requests
Fixes#650 - detect an `Unauthenticated` fetch response and exit the daemon with an error instead of retrying forever
Fixes#766 - add `exec --eventpath` to supply a JSON event payload file
Fixes#256 - add a `bug-report` subcommand that prints version/Go/OS-arch/CPU info
Fixes#617 - add `runner.set_act_env` (default `true`) to optionally omit the `ACT=true` env var
Fixes#635 - record a failure result (and guard a nil reusable-workflow caller) when the job `if`-expression fails to evaluate
Fixes#1005 - remove README docs for config env-var overrides that were already removed from the code
Fixes#448 - clarify in `exec --job` help that `--workflows` may be needed to disambiguate
Fixes#209 - note that `host`-labelled runners still need Docker for `docker://` actions and service containers
Fixes#757 - add a systemd service example with automatic restart
Fixes#474 - add a Kubernetes StatefulSet example that persists the `.runner` registration across reschedules
Fixes#776 - build the basic (non-dind) docker image for `linux/riscv64`
Fixes#628 - build the basic (non-dind) docker image for `linux/s390x`Reviewed-on: https://gitea.com/gitea/runner/pulls/1075
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
