Add optional saved end locations

[ahernsean]

Summary

• add Daniel-scoped saved places with configurable matching radii, shared by all supervising adults
• provide an in-app, interactive OpenStreetMap preview with a touch-adjustable marker and radius circle before a new place is saved
• provide an explicit Cancel action from the preview without saving anything
• optionally capture a one-time device position when ending a drive and prefill a matching place name
• retain manual end-location entry and gracefully continue when location access is declined

Validation

• PYTHONPATH=. .venv/bin/ruff check .
• PYTHONPATH=. .venv/bin/ruff format --check .
• PYTHONPATH=. .venv/bin/mypy
• PYTHONPATH=. .venv/bin/pytest -m "not browser" --cov --cov-report=term-missing --cov-fail-under=95 (110 passed, 95.09%)
• DRIVING_LOG_WEBKIT_WS_ENDPOINT=ws://127.0.0.1:31747/ PYTHONPATH=. .venv/bin/pytest -m browser (4 passed)