Upgrade to pnpm 11

[sneridagh]

Summary

• Pin the repository package manager to pnpm 11.20.0 through the root packageManager field.
• Keep Corepack as the installation and version-selection mechanism for contributors, GitHub Actions, and Read the Docs.
• Install the latest Corepack before enabling it to avoid stale signature metadata.
• Preserve corepack prepare pnpm@* --activate in Read the Docs before the asdf reshim step.
• Move overrides and onlyBuiltDependencies from package.json#pnpm to pnpm-workspace.yaml, where pnpm 11.20.0 reads these settings.
• Update contributor documentation to explain that Corepack resolves the repository-pinned pnpm version.
• Add an Aurora internal towncrier news item.

Why

The repository was pinned to pnpm 10.20.0. Upgrading to the current stable pnpm 11 release keeps the package manager current without adopting the pnpm 12 pre-release and native-binary installation constraints.

The pnpm version remains declared in one place: package.json#packageManager. Corepack reads this field whenever pnpm runs in the repository, ensuring contributors and automated environments use the same exact pnpm release without duplicating the version in workflow or documentation files.

pnpm 11.20.0 no longer reads the root package.json#pnpm configuration block. Moving the existing overrides and build dependency allowlist to pnpm-workspace.yaml preserves their behavior and prevents frozen-install configuration mismatches.

Developer and CI impact

Contributors install and enable current Corepack, then invoke pnpm normally. Corepack downloads and activates pnpm 11.20.0 based on the repository pin.

The shared GitHub Actions setup installs current Corepack before restoring the pnpm store cache and running the existing make install step.

Read the Docs continues to prepare and activate pnpm explicitly before asdf reshim nodejs; repository commands still resolve to the exact package-manager version declared in package.json.

The dependency lockfile does not require regeneration for this upgrade.

Validation

• corepack prepare pnpm@* --activate
• pnpm --version → 11.20.0
• pnpm install --frozen-lockfile --ignore-scripts
• Parsed all changed JSON and YAML configuration files
• git diff --check
• Commit hook: lint-staged