Summary

• Eliminate redundant per-poll work in PilotMarkers and AirportMarkers so unchanged markers cost near-zero reconciliation on every 20-second VATSIM data update
• Role and aircraft image resolution moved inside PilotMarkerItem so React.memo gates the work — stationary pilots with unchanged aircraft/role skip re-render entirely
• Airport markers loop (including TRACON polygons and APP circles) wrapped in useMemo so getAirportByCode, lookupTracon, and Skia image renders only run when data actually changes
• Dead code (ClusteredPilotMarkers) removed

Changes

• PilotMarkers.jsx — role/image resolution moved into child, filter+map memoized, named selector to fix Redux stability warning
• AirportMarkers.jsx — entire markers computation wrapped in useMemo, onPress stabilized with useCallback
• LocalAirportMarker.jsx — custom React.memo equality comparator (checks atcList callsigns, traffic counts, theme)
• CTRPolygons.jsx — onPress stabilized with useCallback
• ClusteredPilotMarkers.jsx — deleted (unused, stale implementation)
• __tests__/PilotMarkers.test.js — updated equality tests for new prop API

Test Plan

• Open map view — pilot markers render correctly at all zoom levels
• ATC markers and TRACON polygons render for active controllers
• Tap a pilot — detail panel opens, tap again closes
• Change theme — pilot icon colors update correctly
• Add a friend CID in settings — friend marker color updates
• No JS-only changes — OTA update sufficient, no native rebuild needed

Notes

Pure JS changes — no native modules touched. OTA-deployable.
Follow-up candidates (deferred): iOS marker rendering pipeline (child <Image> → native image prop), viewport culling for high-density events.