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>

src/files.rs

@@ -199,6 +199,14 @@ pub async fn list_photos<TagD: TagDao, FS: FileSystemAccess>(
     tag_dao: Data<Mutex<TagD>>,
     exif_dao: Data<Mutex<Box<dyn ExifDao>>>,
 ) -> HttpResponse {
+    let mut req = req.into_inner();
+    crate::date_view::apply_day_bounds(
+        &mut req.date_from,
+        &mut req.date_to,
+        req.date_from_day.as_deref(),
+        req.date_to_day.as_deref(),
+        || crate::date_view::owner_display_zone(&app_state.user_ai_prefs_dao),
+    );
     let search_path = &req.path;
 
     let span = tracing::Span::current();
@@ -1176,7 +1184,8 @@ pub async fn get_gps_summary(
 /// Handler for the batch EXIF endpoint at `GET /photos/exif`.
 ///
 /// Returns a single-row projection of `image_exif` for every photo whose
-/// `date_taken` falls in `[date_from, date_to]`, across all libraries.
+/// true instant falls in `[date_from, date_to]` (or the display-zone
+/// `date_from_day` / `date_to_day`), across all libraries.
 /// Designed to replace the N+1 pattern of `/photos` + per-file
 /// `/image/metadata` for window-scoped consumers like Apollo's photo-to-
 /// track matcher: one DB query, one HTTP round-trip, one mutex acquisition.
@@ -1194,6 +1203,14 @@ pub async fn list_exif_summary(
     app_state: Data<AppState>,
 ) -> Result<HttpResponse, actix_web::Error> {
     let span = tracing::Span::current();
+    let mut req = req.into_inner();
+    crate::date_view::apply_day_bounds(
+        &mut req.date_from,
+        &mut req.date_to,
+        req.date_from_day.as_deref(),
+        req.date_to_day.as_deref(),
+        || crate::date_view::owner_display_zone(&app_state.user_ai_prefs_dao),
+    );
 
     span.set_attribute(
         "date_from",