rmaps-online/backlog/tasks/task-12 - Fix-stale-participant-sessions-showing-on-map.md

id	title	status	assignee	created_date	updated_date	labels	dependencies	priority
task-12	Fix stale participant sessions showing on map	Done		2025-12-19 18:00	2025-12-19 18:20	bug ux		high

Description

When opening rMaps, old participant sessions from previous visits are still showing on the map as "ghost" locations. This happens because:

1. Each session generates a new participantId via nanoid()
2. Old participants are persisted in localStorage
3. No cleanup of stale sessions occurs on reload

Fix: Clean up stale participants on room load and use a persistent participant ID per browser.

Acceptance Criteria

• #1 Old participant sessions are cleaned up on room load
• #2 Same user keeps consistent participant ID across sessions
• #3 No ghost duplicates appear on the map
• #4 Build compiles successfully

Implementation Notes

Implementation

1. Added stale participant cleanup (src/lib/sync.ts:133-160)

   • cleanupStaleParticipants() removes participants not seen in last hour
   • Runs automatically when loading room state from localStorage
   • Logs how many stale participants were removed

2. Persistent participant ID (src/hooks/useRoom.ts:30-54)

   • getOrCreateParticipantId() stores a consistent ID per room in localStorage
   • Same user returning to a room gets the same participant ID
   • Prevents creating duplicate ghost entries on each page reload
   • Falls back to temporary ID if localStorage unavailable