fix: calendar filter, habit service, PB 0.25 field compat
- Calendar: remove unsupported due_date!="" filter (PB 0.25 rejects), fetch all + filter client-side
- habit-service: fix active=true filter to archived!=true (field doesnt exist)
- habit-service: remove references to non-existent fields (completed, skipped, score_config, start_date)
- All PocketBase collections: re-added proper data fields with correct PB IDs for relations
Fixes calendar, analytics, habits heatmap, and habits streaks endpoints.