fix(ci): assign every release PR under separate-pull-requests (LAB-898)

[27Bslash6]

Problem

release-please-action@v4 sets outputs.pr to prs[0] only. Since separate-pull-requests: true landed (#87, LAB-888), a cycle can open one release PR per package — but the Assign release PR step only assigned the first, so the others opened unassigned and could sit unnoticed.

Fix

Iterate steps.release.outputs.prs (the JSON array of all opened PRs) and gh pr edit --add-assignee 27Bslash6 each one.

• Guarded on prs_created == 'true' — no-release cycles are a clean no-op.
• Injection-safe: the PR JSON reaches the shell via env: (it carries branch/title text), mirroring pr-title-lint.yml — never inline ${{ }} in run:.
• shell: bash for pipefail: a jq parse failure fails the step instead of silently assigning nothing; a gh failure mid-loop also fails the step.

Verification

The failure mode can't be forced on demand (needs 2+ packages bumping in one cycle), so per the ticket ACs this leans on the confirmed action contract (pr = prs[0], prs = all, verified in the action source) plus a local parse test running the exact loop with gh stubbed:

case	result
2-element prs (incl. ; echo pwned in a title)	both PRs edited, injection inert
1-element (common case)	assigned, no regression
[]	no-op, exit 0
malformed JSON	step fails (exit 5)
gh failure mid-loop	step fails (exit 1)

Docs gate: no docs needed — internal release automation, no user-facing surface.

Closes LAB-898

Summary by CodeRabbit

• Bug Fixes
  • Release pull requests are now consistently assigned across all pull requests included in a release.
  • Improved failure handling ensures release automation reports parsing errors instead of silently continuing.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 19ad90c and 9256fb8.

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• .github/workflows/release-please.yml

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Walkthrough

The release workflow now processes every pull request returned by the release step. It passes the JSON through an environment variable and uses Bash with jq to extract each PR number.

Changes

Release workflow

Layer / File(s)	Summary
Iterate release pull requests .github/workflows/release-please.yml	The workflow replaces the single-PR output with the prs output. It extracts each PR number with jq and assigns every PR. Bash parsing failures now fail the step.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 9256f

This change assigns every newly created release PR while preserving no-op behavior when none are created and failing safely on malformed input or command errors. No actionable merge-blocking risk remains after normal checks and review.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarises the main CI change: assigning every release PR when separate pull requests are enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0 files. (1 skipped: 1 unsupported.)

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch lab-898-assign-all-release-prs

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