fix: mask secrets on every path they leave a job (#1188)

A secret in a matrix value reached the log in the clear:

```yaml
strategy:
  matrix:
    include: "${{ github.token }}"
```

Chasing that one route is pointless, so this masks every sink a secret leaves a job by: the uploaded log rows and the on-disk `job.log`, both through one choke point in `appendLogRow`; the runner's own log, which is where planning errors like that one land with no job logger in reach; the job logger's stdout under debug logging; job summaries; job outputs; and the job name that becomes a container name.

Values the runner knows but the job never declared, the proxy password and the task token, are hidden the same way. Masks apply longest first, since `strings.Replacer` matches in argument order and one secret prefixing another would otherwise mask the prefix and print the rest.

### What changes for users

An output whose value carries a secret is skipped with a warning instead of sent, matching GitHub. Output that showed a secret now shows `***`. `ACTIONS_STEP_DEBUG` and `ACTIONS_RUNNER_DEBUG` are never masked, also matching GitHub, so an output of `true` still reaches the jobs that need it.

Each fix has a test that fails without it.

Reviewed-on: https://gitea.com/gitea/runner/pulls/1188
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>

internal/app/run/runner.go

@@ -519,6 +519,7 @@ func (r *Runner) run(ctx context.Context, task *runnerv1.Task, reporter *report.
 		Env:                  envs,
 		ProxyEnv:             proxyEnv,
 		Secrets:              task.Secrets,
+		ExtraMasks:           append(proxyPasswords(), preset.Token),
 		GitHubInstance:       strings.TrimSuffix(r.client.Address(), "/"),
 		NoSkipCheckout:       true,
 		DisableActEnv:        r.cfg.Runner.SetActEnv != nil && !*r.cfg.Runner.SetActEnv,