fix(personal-records): exclude soft-deleted measurements from PR detection

pr-detection-worker.ts ran its warm-up count and best-measurement scan
across every Measurement row including soft-deleted ones. A user who
deleted a row that happened to be their PR would not get the next-best
row promoted on the next detection pass. Add `deletedAt: null` to both
where clauses to align with the v1.4.40 soft-delete completeness sweep.

Also document the offhost-backup DR-intent at the matching findMany —
that path deliberately includes soft-deleted rows because the offhost
upload is a disaster-recovery snapshot, not a user-facing export.

src/lib/jobs/offhost-backup.ts

@@ -216,6 +216,9 @@ export async function runOffhostBackup(
     try {
       const [measurements, medications, intakeEvents, moodEntries] =
         await Promise.all([
+          // includes soft-deleted rows because this is the DR snapshot,
+          // not a user-facing export — see
+          // `/api/export/full-backup/route.ts` for the symmetric exclusion.
           prisma.measurement.findMany({ where: { userId: user.id } }),
           prisma.medication.findMany({
             where: { userId: user.id },

src/lib/personal-records/pr-detection-worker.ts

@@ -217,7 +217,7 @@ export async function detectPersonalRecordsForUser(
     // Warm-up gate. Cheap count first so we don't pull a 30k-row
     // scan on a brand-new account.
     const sampleCount = await prisma.measurement.count({
-      where: { userId, type: metricType },
+      where: { userId, type: metricType, deletedAt: null },
     });
     if (sampleCount < PR_DETECTION_WARMUP_THRESHOLD) continue;
 
@@ -400,7 +400,7 @@ async function findBestMeasurement(
   direction: PersonalRecordDirection,
 ): Promise<MeasurementCandidate | null> {
   const row = await prisma.measurement.findFirst({
-    where: { userId, type },
+    where: { userId, type, deletedAt: null },
     orderBy:
       direction === PersonalRecordDirection.MAX
         ? { value: "desc" }