chore(deps): ruff, ty, coverage, packaging (#73)

## Summary

Dependabot's grouped minor-patch bump (`ruff` 0.16.1 to 0.16.2, `ty`
0.0.66 to 0.0.69), plus the rest of the pass carried in the same PR so
this repo needs one merge rather than three: `coverage` 7.15.3 to 7.15.4
and `packaging` 26.2 to 26.3, both of which a lock upgrade showed still
outstanding.

All four are development tooling. Nothing in the published dependency
set moves.

## Type of change

- [ ] Bug fix (no breaking change)
- [ ] New feature (no breaking change)
- [ ] Breaking change (existing callers must update)
- [x] Docs, tests, or internal maintenance only

## Public API

None. No exported type, signature, wire format, or response shape
changes, and no runtime dependency moves.

## Test plan

Run locally on this branch, all green: `uv run ruff check .`, `uv run ty
check`, and `uv run pytest` (183 passed, 8 skipped, 100% coverage
against the 95% floor).

## Checklist

- [x] Tests cover the new behavior, and the suite passes locally
- [x] Lint, format, and type checks pass
- [x] Docs and README examples updated if the public surface changed
- [x] No secrets, credentials, or personal data in the diff or the tests

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: vvillait88 <vvillait88@yahoo.com>

Author: dependabot[bot]