fix(ci): expose failed upstream sync results

[pRizz]

Summary

• Print the structured upstream sync result to the Actions log when scripts/github-actions/upstream-sync.sh run-sync sees bun run sync:upstream --json exit nonzero.
• Keep successful sync runs quiet and leave the existing summary/result output contract unchanged.
• Add shell-wrapper coverage for both the failed-sync logging path and the quiet success path, and include it in bun run test:deploy.

Verification

• bun test scripts/github-actions/upstream-sync-sh.test.ts scripts/github-actions/upstream-sync-summary.test.ts scripts/lib/upstream-sync-main.test.ts scripts/lib/upstream-sync.test.ts
• bun run test:deploy
• bun run biome:check
• bun run studio:lint
• bun run typecheck
• bun run studio:typecheck
• bun run --filter @openlinks/studio-api test
• bun run studio:test:integration

Upstream PR hygiene

• Branch rebuilt from upstream/main.
• Fork-owned paths excluded from git diff --stat upstream/main...HEAD; the PR diff is limited to package.json and scripts/github-actions/*.