Migrate uv dev-dependencies to dependency-groups

[tejas0077]

uv now warns that tool.uv.dev-dependencies is deprecated and will be removed:

warning: The `tool.uv.dev-dependencies` field (used in `pyproject.toml`) is
deprecated and will be removed in a future release; use
`dependency-groups.dev` instead

This moves the same four dev requirements to [dependency-groups] dev. No
requirements changed and uv.lock is unaffected (uv lock produces no diff).
CI's uv sync --dev picks up the dev group by default, so the workflow
needs no changes. All 511 tests pass locally.

[greptile-apps]

Confidence Score: 5/5

[Low impact] This PR appears safe to merge.

Summary

Moves the four development requirements from tool.uv.dev-dependencies to dependency-groups.dev.

• The project declares its development tools in uv’s dev group.

_{Reviews (1) · Last reviewed commit: "Migrate uv dev-dependencies to dependenc..." · Reviewed by Greptile}