feat(dates): calendar-day date filters in the owner's display zone (#152)

/photos, /photos/exif and unified search take date_from_day /
date_to_day (YYYY-MM-DD): the server turns them into the first day's
start and the last day's end in the owner's display zone, the same days
/memories groups by. Each replaces its instant counterpart. Clients stop
computing midnights in the device's zone, which drifted by the travel
offset whenever the phone's zone differed from display_tz.

e2e check: every fixture is included by its display-zone day and
excluded by the days either side.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dev/e2e/check_wall_clock.py

@@ -7,7 +7,10 @@ For every indexed fixture, the manifest's expected wall clock must equal the
 `/photos/exif`; and `/image/metadata` / `/photos/exif`'s `true_instant` must
 equal the expected instant. The `/photos/exif` date filter must also treat
 that instant as a range edge (#152): `[t, t]` includes the file, and a range
-ending at `t - 1` or starting at `t + 1` excludes it. One disagreement
+ending at `t - 1` or starting at `t + 1` excludes it; and filtering by the
+file's calendar day in the owner's display zone (`date_from_day` /
+`date_to_day`) includes it, while the day before or after excludes it. One
+disagreement
 anywhere is exactly the class of bug these fields exist to end, so any
 mismatch fails the run.
 
@@ -19,9 +22,13 @@ import os
 import subprocess
 import sys
 import urllib.parse
+from datetime import datetime, timedelta, timezone
 from pathlib import Path
+from zoneinfo import ZoneInfo
 
 E2E = Path(__file__).with_name("e2e.sh")
+# The owner's display zone in the e2e env (no prefs row → the app default).
+DISPLAY_ZONE = ZoneInfo("America/New_York")
 
 
 def api(path: str) -> dict:
@@ -44,6 +51,10 @@ def main() -> int:
         rows = api(f"photos/exif?date_from={lo}&date_to={hi}")["photos"]
         return any(r["file_path"] == path for r in rows)
 
+    def in_exif_days(path: str, first: str, last: str) -> bool:
+        rows = api(f"photos/exif?date_from_day={first}&date_to_day={last}")["photos"]
+        return any(r["file_path"] == path for r in rows)
+
     failures = 0
     for item in items:
         path, want = item["path"], item["wall_clock"]
@@ -70,6 +81,14 @@ def main() -> int:
                 bad["photos/exif [.., t-1]"] = "included"
             if in_exif_range(path, t + 1, t + 86_400):
                 bad["photos/exif [t+1, ..]"] = "included"
+            # Calendar days are the owner's display-zone days (#152).
+            day = datetime.fromtimestamp(t, timezone.utc).astimezone(DISPLAY_ZONE).date()
+            iso = lambda d: d.isoformat()
+            if not in_exif_days(path, iso(day), iso(day)):
+                bad[f"photos/exif day {day}"] = "excluded"
+            for other in (day - timedelta(days=1), day + timedelta(days=1)):
+                if in_exif_days(path, iso(other), iso(other)):
+                    bad[f"photos/exif day {other}"] = "included"
         if bad:
             failures += 1
             print(f"MISMATCH {path}: expected {want}, got {bad}")