Merges the `gitea.com/gitea/act` fork into this repository as the `act/`
directory and consumes it as a local package. The `replace github.com/nektos/act
=> gitea.com/gitea/act` directive is removed; act's dependencies are merged
into the root `go.mod`.
- Imports rewritten: `github.com/nektos/act/pkg/...` → `gitea.com/gitea/act_runner/act/...`
(flattened — `pkg/` boundary dropped to match the layout forgejo-runner adopted).
- Dropped act's CLI (`cmd/`, `main.go`) and all upstream project files; kept
the library tree + `LICENSE`.
- Added `// Copyright <year> The Gitea Authors ...` / `// Copyright <year> nektos`
headers to 104 `.go` files.
- Pre-existing act lint violations annotated inline with
`//nolint:<linter> // pre-existing issue from nektos/act`.
`.golangci.yml` is unchanged vs `main`.
- Makefile test target: `-race -short` (matches forgejo-runner).
- Pre-existing integration test failures fixed: race in parallel executor
(atomic counters); TestSetupEnv / command_test / expression_test /
run_context_test updated to match gitea fork runtime; TestJobExecutor and
TestActionCache gated on `testing.Short()`.
Full `gitea/act` commit history is reachable via the second parent.
Co-Authored-By: Claude (Opus 4.7) <noreply@anthropic.com>
