fix: sync refactor — fix 6 bugs + cache refresh na sync

- setDeletedAt update nu ook updatedAt (bug 2)
- getAllMeasurements filtert deletedAt IS NULL, nieuwe getAllMeasurementsForSync voor sync
- mergeMeasurements detecteert server deleted:true → deletedAt (bug 1)
- syncAll: pull-push split met remoteUpdatedMap, geen double-push (bug 3)
- hard delete alleen na API-succes (bug 4)
- DashboardScreen: refreshCache() na syncAll zodat UI niet op Laden blijft hangen
- deleteMeasurement() dead code verwijderd (bug 5)
- tests: 3 nieuwe testcases voor deleted → deletedAt mapping, 15/15 pass

src/store/measurementStore.ts

@@ -0,0 +1,59 @@
+import { Measurement } from '../types'
+import { initDatabase, getAllMeasurements, getLatestMeasurements, getMeasurementsSince } from '../database/db'
+
+let cachedMeasurements: Measurement[] = []
+let initialized = false
+
+export async function loadFromDb(): Promise<Measurement[]> {
+  await initDatabase()
+  cachedMeasurements = await getAllMeasurements()
+  initialized = true
+  return cachedMeasurements
+}
+
+export async function loadLatest(count: number): Promise<Measurement[]> {
+  await initDatabase()
+  const latest = await getLatestMeasurements(count)
+  cachedMeasurements = latest
+  initialized = true
+  return latest
+}
+
+export async function loadSince(date: string): Promise<Measurement[]> {
+  await initDatabase()
+  const since = await getMeasurementsSince(date)
+  // Merge with existing cache (keep newer measurements)
+  const existingIds = new Set(cachedMeasurements.map(m => m.id))
+  const newOnes = since.filter(m => !existingIds.has(m.id))
+  cachedMeasurements = [...cachedMeasurements, ...newOnes]
+  cachedMeasurements.sort((a, b) => new Date(b.measuredAt).getTime() - new Date(a.measuredAt).getTime())
+  return cachedMeasurements
+}
+
+export function getCached(): Measurement[] {
+  return cachedMeasurements
+}
+
+export function updateCache(m: Measurement): void {
+  const idx = cachedMeasurements.findIndex(x => x.id === m.id)
+  if (idx >= 0) {
+    cachedMeasurements[idx] = m
+  } else {
+    cachedMeasurements.unshift(m)
+  }
+  // Re-sort by measuredAt descending
+  cachedMeasurements.sort((a, b) => new Date(b.measuredAt).getTime() - new Date(a.measuredAt).getTime())
+}
+
+export function removeFromCache(id: string): void {
+  cachedMeasurements = cachedMeasurements.filter(m => m.id !== id)
+}
+
+export async function refreshCache(): Promise<Measurement[]> {
+  await loadFromDb()
+  return cachedMeasurements
+}
+
+export function isInitialized(): boolean {
+  return initialized
+}