fix: improve behaviour across masking, commands and status (#1194)

Fixes 51 bugs discovered via comparison with `actions/runner`. Every fix has test coverage.

### Secrets

- A short secret registered no shifted-base64 form, so `base64("user:$TOKEN")` printed in the clear
- Encoded forms came only from the whole trimmed value, missing padded and per-line spellings
- Masks split only on `\n`, so `::add-mask::a%0Db` registered neither half
- Adds XML, expression-string and quote-trimming encoders

### Workflow commands

- Split at the last `::` or `]` rather than the first, so `::add-mask::a::b` registered no mask
- A command on the last line without a newline was ignored, and `::ADD-MASK::` did nothing
- `##[...]` did not decode `%3B`/`%5D`, properties lost anything after a second `=`
- `$GITHUB_ENV` and `::set-env::` now refuse `NODE_OPTIONS`

### Status

- `continue-on-error` reported failed, a cancelled job reported success, an `if:` error reported cancelled
- File commands ran after `continue-on-error`, failing the job while the step stayed green
- A bad job output aborted the whole run instead of that job

### Steps and actions

- `${{ matrix.* }}` and `${{ strategy.* }}` were empty inside composite actions
- Composite inputs leaked into nested actions as `INPUT_*`, `with:` matched case-sensitively, `pre` failures were dropped
- Docker actions dropped `runs.env` when the caller passed `with: args:`, and caller `args`/`entrypoint` beat the manifest
- An implicit shell ran with `pipefail`, a `shell:` without `{0}` passed without running
- `container.env` overrode job env and every `$GITHUB_ENV` write, heredocs lost leading blank lines, `$GITHUB_PATH` was not BOM-decoded

Written by Claude Opus 5.

Reviewed-on: https://gitea.com/gitea/runner/pulls/1194
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>

act/runner/job_executor.go

@@ -236,6 +236,13 @@ func newJobExecutor(info jobInfo, sf stepFactory, rc *RunContext) common.Executo
 
 	// Ahead of the teardown below, while the job environment is still up.
 	postExecutor = postExecutor.Finally(rc.runJobCompletedHook)
+	postExecutor = postExecutor.Finally(func(ctx context.Context) error {
+		// swallowed: a bad output fails this job, it must not abandon the rest of the plan
+		if err := info.interpolateOutputs()(ctx); err != nil {
+			reportStepError(ctx, rc, err)
+		}
+		return nil
+	})
 
 	postExecutor = postExecutor.Finally(func(ctx context.Context) error {
 		jobError := common.JobError(ctx)
@@ -267,7 +274,6 @@ func newJobExecutor(info jobInfo, sf stepFactory, rc *RunContext) common.Executo
 			defer cancel()
 			return postExecutor(postCtx)
 		}).
-		Finally(info.interpolateOutputs()).
 		Finally(info.closeContainer()))
 }
 
@@ -365,7 +371,7 @@ func setJobResult(ctx context.Context, info jobInfo, rc *RunContext, success boo
 	// concurrent succeeding one.
 	job := rc.Run.Job()
 	var continueOnError bool
-	if !success {
+	if !success && !rc.jobCancelled {
 		// Use a fresh context so an expired job timeout cannot block expression evaluation.
 		evalCtx := common.WithLogger(context.Background(), common.Logger(ctx))
 		continueOnError = evaluateJobContinueOnError(evalCtx, rc, job)
@@ -378,7 +384,11 @@ func setJobResult(ctx context.Context, info jobInfo, rc *RunContext, success boo
 		if len(info.matrix()) > 0 && job.Result != "" {
 			result = job.Result
 		}
-		if !success {
+		// cancelled is sticky, so a sibling combination finishing last cannot mask it
+		switch {
+		case rc.jobCancelled:
+			result = "cancelled"
+		case !success && result != "cancelled":
 			result = "failure"
 			job.SetContinueOnError(continueOnError)
 		}
@@ -392,9 +402,12 @@ func setJobResult(ctx context.Context, info jobInfo, rc *RunContext, success boo
 		return
 	}
 
-	jobResultMessage := "succeeded"
-	if jobResult != "success" {
-		jobResultMessage = "failed"
+	jobResultMessage := "failed"
+	switch jobResult {
+	case "success":
+		jobResultMessage = "succeeded"
+	case "cancelled":
+		jobResultMessage = "cancelled"
 	}
 
 	logger.WithField("jobResult", jobResult).Infof("Job %s", jobResultMessage)