`update-pull-request` target from a `safe-outputs.needs` job output is blanked in the agent config and rejected on `workflow_dispatch`

[tsm-harmoney]

Summary

When update-pull-request.target is set to the output of a job listed in safe-outputs.needs, the compiler
replaces it with "" in the agent job's safe-outputs config. The MCP server treats "" as triggering and
rejects every update_pull_request call on workflow_dispatch, although the handler job's config still has
the correct PR number.

Reproduction

on:
  workflow_dispatch:

jobs:
  setup:
    runs-on: ubuntu-latest
    outputs:
      pull_request_number: ${{ steps.create-pr.outputs.pull_request_number }}
    steps:
      - id: create-pr
        run: echo "pull_request_number=123" >> "$GITHUB_OUTPUT"

# the agent job depends on setup, so needs.setup resolves there
steps:
  - run: echo "PR #${{ needs.setup.outputs.pull_request_number }}"

safe-outputs:
  needs: [setup]
  update-pull-request:
    target: ${{ needs.setup.outputs.pull_request_number }}

After gh aw compile:

Config	update_pull_request.target
Agent job (GH_AW_SAFE_OUTPUTS_CONFIG)	""
safe_outputs job (GH_AW_SAFE_OUTPUTS_HANDLER_CONFIG)	${{ needs.setup.outputs.pull_request_number }}

The agent's update_pull_request call is then rejected with:

update_pull_request requires a pull request context but the workflow is running on a "workflow_dispatch" event. [...] the workflow must configure update-pull-request: target: '*' and you must supply pull_request_number.

Expected

The PR number is accepted as a fixed target, as
documented
("triggering" (default), "*", or number).

Root cause

Line references are for v0.89.21.

1. sanitizeAgentSafeOutputsConfig (pkg/workflow/compiler_safe_outputs_builder.go:181, added in Fix actionlint error: agent job referencing needs.approval_allowlist it never depends on #54028)
   blanks needs.<job> expressions for every job in safe-outputs.needs, assuming the agent job never
   depends on those jobs. Here the agent job does depend on setup, so the expression would resolve fine.
2. actions/setup/js/safe_outputs_handlers.cjs:2990 falls back to "triggering" for an empty target
   (updatePRConfig.target || "triggering"), so the blanked fixed target becomes a triggering target.

Suggested fix

• Only blank needs.<job> references for jobs the agent job does not depend on, and/or
• don't treat a blanked target as triggering in the MCP server; leave the check to the handler.

Versions

• Works: v0.85.4
• Broken: v0.87.2 and later, including v0.89.22 and main

Thanks for all your work on gh-aw!