Three issues fixed:
1. GPX parser used browser DOMParser which doesn't exist in Node/Vite SSR.
Added async parseGpxAsync() using linkedom for server-side parsing.
2. Server-side session initialization stored waypoints in a Yjs doc
instance separate from the Vite WebSocket plugin's doc store.
Moved waypoint initialization to client-side: API returns parsed
waypoints, client adds them to Yjs after sync.
3. GPX was encoded in URL params causing HTTP 431. Now the Journal
creates a Planner session via API (POST body), and only passes
compact waypoint coordinates in URL params.
Verified: Journal route → Edit in Planner → 4 waypoints loaded,
route computed (79.3km), elevation profile, Save to Journal ready.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
