feat(ci): schema-drift CI gate against live GitLab (DOT-559)

[ichoosetoaccept]

Closes Phase 4 of the response-schemas initiative (DOT-555). Adds a
weekly GitHub Actions workflow plus a standalone Bun script that calls
every response-schema-bearing GitLab REST endpoint and parses each
response against its declared Zod schema with .parse() (strict).
Phase 1 deliberately made runtime parsing lenient (.safeParse + log +
pass-through) so users aren't blocked by minor drift; this is the
strict counterpart that catches API drift in CI.

The script auto-discovers fixture IDs from list endpoints — no
per-endpoint env var sprawl. Re-uses loadConfig() and GitLabClient
from the runtime. Required env vars: GITLAB_API_URL,
GITLAB_PERSONAL_ACCESS_TOKEN, GITLAB_PROJECT_ID.

Note

Add schema-drift CI gate that validates live GitLab responses against Zod schemas

• Adds scripts/check-schema-drift.ts, a Bun CLI that calls live GitLab REST endpoints (projects, merge requests, commits, issues, pipelines, users, repository tree) and strictly validates responses with Zod .parse(), exiting non-zero on any mismatch.
• Adds .github/workflows/schema-drift.yml, a weekly cron workflow (Mondays 06:00 UTC) and workflow_dispatch trigger that runs the drift check using repo secrets for GitLab credentials.
• Adds a drift script to package.json for running the same check locally via bun run drift.
• Updates README.md with troubleshooting guidance for schema validation warnings and instructions for running the drift check manually.
• Fetch logic includes retry with backoff for transient 5xx and network errors, but schema mismatches are never retried — they are the intended failure signal.

🖇️ Linked Issues

Completes DOT-559, the Phase 4 subtask of DOT-555 (Introduce Zod response schemas as a token-efficiency primitive).

^{Macroscope summarized 8e00818.}

[ichoosetoaccept]

This change is part of the following stack:

• feat(ci): schema-drift CI gate against live GitLab (DOT-559) #112 ◀

_{Change managed by git-spice.}

[linear-code]

DOT-559

DOT-555

[macroscopeapp]

Approvability

Verdict: Approved

This PR adds CI-only infrastructure (a scheduled workflow and validation script) for detecting schema drift against live GitLab APIs. No production runtime code is modified - the changes are purely testing/validation tooling.

^{You can customize Macroscope's approvability policy. Learn more.}

[ichoosetoaccept]

@macroscopeapp review

[github-actions]

🎉 This PR is included in version 2.33.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀