fix(import): cut lab CSV duplicate days in the zone the file is read in

The rows were parsed in the query's timezone while the duplicate keys
used the account's, so two draws on separate days of the file's zone
could collapse into one, or one day split in two.

tests/integration/record-csv-import.test.ts

@@ -176,6 +176,33 @@ describe("lab CSV import", () => {
   });
 });
 
+describe("lab CSV import in a zone of the file's own", () => {
+  it("cuts the duplicate day in the zone the file is read in", async () => {
+    // Read in New York, these are draws on two days (1 and 2 March). In the
+    // account's Berlin they both fall on 2 March, which used to make the
+    // second a duplicate of the first.
+    const csv = [
+      "Analyt;Wert;Einheit;Datum",
+      "Zone marker;7;mg/dL;2025-03-01T22:30",
+      "Zone marker;7;mg/dL;2025-03-02T02:00",
+    ].join("\n");
+    const result = await importLabsCsv({
+      userId: USER,
+      tz: TZ,
+      stream: textToStream(csv),
+      maxBytes: 1_000_000,
+      query: labsCsvQuerySchema.parse({
+        analyte: "0",
+        value: "1",
+        unit: "2",
+        date: "3",
+        timezone: "America/New_York",
+      }),
+    });
+    expect(result).toMatchObject({ inserted: 2, duplicates: 0 });
+  });
+});
+
 describe("medication CSV import", () => {
   const MEDS = [
     "name,dose,times,as needed,start,end",