fix(ci): gate every pull request against its base

[chh-ay]

Problem

CI currently runs only for pull requests targeting develop. A feature PR targeting a release branch therefore receives no checks. The Changesets gate also always compares with origin/develop, so a PR into another base can inherit changesets from earlier branch work.

Change

• run CI for pull requests targeting any base branch while retaining push CI only on develop
• resolve GITHUB_BASE_REF once, with an origin/develop fallback outside PR context
• use that same ref for both the package-size-history diff and Changesets --since argument
• contract the exact trigger policy and all comparison values, including a non-version release branch
• include the new focused test in test:tooling

This intentionally avoids hardcoding 0.4.0; future release branches inherit correct CI and comparison behavior without another workflow edit. release.yml and version.yml remain develop-only.

Verification

• bun test scripts/changeset-ci.test.ts scripts/workflow-contract.test.ts — 13 pass, 0 fail
• bun run test:tooling — 140 pass, 0 fail
• bun run typecheck — passed for all workspaces and verification consumers
• bun run lint — passed with the existing 2 MiB corpus size warning only
• GITHUB_BASE_REF=develop bun run changeset:ci — passed; empty tooling changeset, no package bump
• Preflight checkout already uses fetch-depth: 0, so origin/<base> is available without a job change

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
sheetwrite	Ready	Preview, Comment	Jul 26, 2026 2:40pm