build(viewer): migrate dev deps from [project.optional-dependencies] to PEP 735 [dependency-groups] #620

Background

PR #595 surfaced unstaged changes adding PEP 735 [dependency-groups] blocks to:

• data-management/viewer/pyproject.toml
• data-management/viewer/backend/pyproject.toml

Those additions duplicate the existing [project.optional-dependencies].dev declarations rather than replacing them, so they were intentionally not included in PR #595 to keep that PR scoped to the episode viewer test fixes.

Goal

Cleanly migrate dev dependencies in both data-management/viewer pyproject.toml files from the legacy PEP 621 [project.optional-dependencies].dev block to the modern PEP 735 [dependency-groups].dev block, and update tooling (uv, CI) to install via --group dev.

Tasks

• Replace [project.optional-dependencies].dev with [dependency-groups].dev in data-management/viewer/pyproject.toml (full set: h5py, httpx, hypothesis, pytest, pytest-asyncio, schemathesis, slowapi, ruff, etc.)
• Replace [project.optional-dependencies].dev with [dependency-groups].dev in data-management/viewer/backend/pyproject.toml (full set matching the current legacy block)
• Re-run uv lock in both directories to refresh uv.lock
• Update any CI / pre-commit / setup scripts that currently install via uv sync --extra dev to use uv sync --group dev
• Verify pytest, ruff, and frontend npm run validate still pass with the new install path
• Confirm no other consumer (Dockerfile, devcontainer, GitHub Actions) still references the legacy dev extra

Out of Scope

• Migrating other top-level packages (training/, evaluation/, data-pipeline/) — file follow-ups per package as needed.
• Restructuring runtime dependencies.

References

• PEP 735 — Dependency Groups
• uv dependency groups docs
• PR test(viewer): add dashboard and episode-viewer component tests #595 (origin of the discovery)