ci: harden uv dependency installs

[raoabinav]

Summary

• Adds uv HTTP retry/timeout settings for the large build matrix so transient PyPI/CDN stalls do not fail PR runs immediately.
• Enables setup-uv cache for lint, type-check, and wheel-build jobs using uv.lock as the cache dependency key.
• Wraps uv build/install calls that touch remote dependencies with bounded retries.
• Disables matrix fail-fast so one infrastructure timeout does not cancel the remaining platform signal.

Context

Recent PR runs failed on macOS Intel before tests executed because uv timed out while downloading PyPI wheels such as pandocfilters and jupyter-core. This PR hardens the workflow against that failure mode without changing package code.

Validation

• Parsed .github/workflows/build-reusable.yml locally with Ruby YAML loader.
• Ran git diff --check.

[raoabinav]

Parking this PR for now to keep the review queue focused on #347. I’ll revisit/reopen this work later as a smaller clean PR once the content-hash PR lands.

[raoabinav]

Reopening this now that #347 has landed. This is intentionally scoped to CI reliability only: uv retries/timeouts, setup-uv cache, bounded retries around uv build/install steps, and fail-fast disabled so one transient download failure does not cancel the rest of the matrix.