Improve roving map origin markers

[rwjblue]

BLUF: Make roving map origins easier to identify by numbering each origin marker and showing richer origin callouts.

This assigns each unique origin grid an order number based on the first QSO from that origin. Multi-origin operations render those origins as small tappable numbered markers so the sequence remains visible on the map.

Origin callouts now use the active activation ref when available, falling back to the grid or coordinates. They also show the QSO count and the first-to-last QSO duration for that origin when multiple timestamps are available.

Scope

• Deduplicate origins by active origin grid/location.
• Order origins by first QSO time.
• Render numbered origin markers for multi-origin maps.
• Keep the existing single-origin dot behavior when there is only one
  origin.
• Show generic activation ref/name, QSO count, and elapsed QSO span in
  origin callouts.

Stack

1. main
2. Use section timeline context for roving map QSO origins #204
3. 👉 rwjblue/number-map-origin-dots

This draft currently depends on the preceding roving-map stack because
GitHub does not expose fork PR head branches as base branches in the
upstream repository. After the prior PR lands, this PR should be rebased
so the diff contains only the origin marker and callout changes.

Screenshots

Multi location

Single Location