Add isNaN() checks in addition to isFinite() to catch NaN values before
they reach Leaflet's polyline renderer. This prevents 'can't access
property x, h is undefined' errors when invalid coordinates slip through.
Generated with Claude Code https://claude.com/claude-code
When changing trail duration and historical data settings, historical positions
would show up on the map but trail lines wouldn't connect them. This was caused
by a mismatch between trail ID generation and callsign extraction.
## Changes
- Fix getTrailId() to properly extract base callsigns from historical marker IDs
- Add setTrailDuration() method to TrailManager for dynamic duration updates
- Add LiveView event to synchronize trail duration changes with client
- Add comprehensive tests for historical ID handling
## Problem
Historical markers have IDs like "hist_CALLSIGN_123" but getTrailId() was
returning the full ID while TrailManager.extractBaseCallsign() extracted just
"CALLSIGN", creating separate trails instead of connected ones.
## Solution
Updated getTrailId() to extract base callsigns from historical IDs using the
same logic as TrailManager, ensuring all positions from the same station use
the same trail ID and connect properly.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
