style(e2e): ruff auto-fix import sorting in coord + vpair + tests

Four I001 violations surfaced when running ruff over the full src/
tests/ tree (the CI command) rather than just the testing subpath:
- src/gps_denied/testing/coord.py
- src/gps_denied/testing/datasets/vpair.py
- tests/e2e/test_coord.py
- tests/e2e/test_vpair_adapter.py

All auto-fixable; no behavioural change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/gps_denied/testing/coord.py

@@ -10,7 +10,6 @@ from __future__ import annotations
 
 import math
 
-
 # WGS84 constants
 _A = 6_378_137.0                 # semi-major axis, metres
 _F = 1.0 / 298.257223563         # flattening