feat(agenda): Epic 0 - Database schema for agenda module

- E0.S1: Add encounter_id and intake_id columns to reports table
- E0.S2: Add performance indices for reports and encounters
- E0.S3: Regenerate TypeScript types

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

supabase/migrations/20251202_add_agenda_indices.sql

@@ -0,0 +1,28 @@
+-- ============================================================================
+-- Migration: Add performance indices for agenda module
+-- Epic: E0 - Database & Types
+-- Story: E0.S2 - Index toevoegen voor performance
+-- ============================================================================
+
+-- Index for reports.encounter_id (find reports linked to an encounter)
+CREATE INDEX IF NOT EXISTS idx_reports_encounter ON reports(encounter_id)
+  WHERE encounter_id IS NOT NULL AND deleted_at IS NULL;
+
+-- Index for reports.intake_id (find reports linked to an intake)
+CREATE INDEX IF NOT EXISTS idx_reports_intake ON reports(intake_id)
+  WHERE intake_id IS NOT NULL AND deleted_at IS NULL;
+
+-- Index for encounters.period (date range queries for calendar views)
+CREATE INDEX IF NOT EXISTS idx_encounters_period ON encounters(period_start, period_end);
+
+-- Index for encounters.practitioner (filter by behandelaar)
+CREATE INDEX IF NOT EXISTS idx_encounters_practitioner ON encounters(practitioner_id)
+  WHERE practitioner_id IS NOT NULL;
+
+-- ============================================================================
+-- Verification
+-- ============================================================================
+DO $$
+BEGIN
+  RAISE NOTICE '✓ Migration E0.S2 completed - indices created';
+END $$;