CI: scope pnpm install per job with --filter to skip unneeded packages

[odinr]

Context

.github/actions/node-setup/action.yml runs an unfiltered pnpm install --frozen-lockfile for every job in every workflow that uses it (ci.yml, pr.yml, next.yml, pre-release.yml, generate-docs.yml, index-docs.yml, copilot-setup-steps.yml). Since it's a monorepo, this installs the entire workspace regardless of what a given job actually touches.

Concretely: packages/cli-plugins/copilot depends on @github/copilot-sdk and agent-browser for its app eval command. @github/copilot-sdk's optional native binary (@github/copilot-darwin-arm64 locally, linux-x64 equivalent on CI) alone is ~326MB. Jobs like pr.yml's code-quality (lint/build) never touch the copilot plugin but still pay to install it on every run.

Proposal

Add an optional filter input to node-setup/action.yml that gets passed through to pnpm install --frozen-lockfile --filter <value>, and set it per-workflow/per-job based on what that job actually needs (e.g. exclude packages/cli-plugins/copilot from jobs that only build/lint/test the rest of the workspace).

Risks / open questions

• Need to verify each job's actual transitive needs before narrowing the filter — a wrong exclusion could silently skip installing something a job needs.
• ci.yml's release-pkg job publishes the whole monorepo, so it likely needs to stay unfiltered.
• Worth checking whether turbo's own affected-package detection already covers some of this at the task level, separate from the install step.

Related

Follow-up from investigating CI cache size — see .github/actions/node-setup/action.yml (cache-only-save-on-main change) and the agent-browser/@github/copilot-sdk dependency scoping.