fix: job container, daemon startup, action cache and exec fixes (#1294)

- Keep `GITHUB_ENV`, `GITHUB_OUTPUT`, `GITHUB_STATE` and `GITHUB_PATH` when a job times out or is cancelled, so post steps still get their state
- Retry the startup Declare while Gitea is unreachable instead of exiting, still failing fast on rejected registrations, auth and misconfiguration
- Reuse a local image when a platform variant such as `linux/arm/v7` is requested instead of pulling again
- Read `PATH` from the created job container so cross-architecture jobs get tool paths for the right architecture
- Extract action copies relative to the act volume so they never cross an image's `/var/run` symlink, which rootless Podman rejects
- Keep the job container's entrypoint when container options set `--entrypoint`, warning instead of appending it to the keep-alive command
- Lock action cache entries across runner processes that share a cache directory
- `exec`: omit `GITHUB_SERVER_URL` and `GITHUB_API_URL` without `--gitea-instance` instead of exporting a bare `https://`, and read owner and repository from any origin remote

Reviewed-on: https://gitea.com/gitea/runner/pulls/1294
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>

scripts/test-dind.sh

@@ -9,7 +9,7 @@
 #
 # Usage: scripts/test-dind.sh [target] [-- go-test-args...]
 #   target:        dind (default), dind-rootless, or podman to run PODMAN_TEST_IMAGE's API service instead
-#   go-test-args:  passed verbatim to `go test`. Defaults cover image env extraction,
+#   go-test-args:  passed verbatim to `go test`. Defaults cover image platform detection,
 #                  symlink copying, a mounted Docker job using cached images and the
 #                  image's s6 supervision, or the Docker proxy probe for podman.
 #
@@ -55,7 +55,7 @@ else
   daemon_args=(-e DOCKER_TLS_CERTDIR= --entrypoint dockerd-entrypoint.sh "$image" --host=tcp://0.0.0.0:2375)
   if [ $# -eq 0 ]; then
     default_tests=true
-    set -- -count=1 -race -run '^TestDocker$' ./act/container/
+    set -- -count=1 -race -run '^TestImageExistsLocally$' ./act/container/
   fi
 fi