Redirect manual date edits on a version path to its original (#194)

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

src/handlers/image.rs

@@ -926,6 +926,29 @@ fn earliest_fs_time(response: &MetadataResponse) -> Option<i64> {
     }
 }
 
+/// A manual date on a photo version (#191) is overwritten by the next
+/// metadata sync (`sync_version_metadata` re-copies the original's date), so
+/// the edit is redirected to the original, as tag writes are. Returns the
+/// `(library, path)` the edit applies to: the original's when `path` is a
+/// linked version with a live original, else the inputs unchanged.
+fn date_edit_target<'a>(
+    app_state: &'a AppState,
+    library: &'a libraries::Library,
+    path: &str,
+) -> (&'a libraries::Library, String) {
+    let original = app_state
+        .version_dao
+        .lock()
+        .expect("Unable to lock VersionDao")
+        .original_location_of(library.id, path)
+        .ok()
+        .flatten();
+    match original {
+        Some((lib_id, rel)) => (app_state.library_by_id(lib_id).unwrap_or(library), rel),
+        None => (library, path.to_string()),
+    }
+}
+
 #[post("/image/exif/date")]
 #[tracing::instrument(name = "set_image_date", skip_all)]
 pub async fn set_image_date(
@@ -949,6 +972,7 @@ pub async fn set_image_date(
     // Path normalization matches set_image_gps so a Windows-import client
     // doesn't end up with a backslash variant that misses the row.
     let normalized_path = body.path.replace('\\', "/");
+    let (library, normalized_path) = date_edit_target(&app_state, library, &normalized_path);
 
     // The user's display zone — the wall the UI sent is rendered in this
     // zone (ADR-0001, ticket #115). NULL / unparseable prefs fall back to
@@ -1012,6 +1036,7 @@ pub async fn clear_image_date(
     };
 
     let normalized_path = body.path.replace('\\', "/");
+    let (library, normalized_path) = date_edit_target(&app_state, library, &normalized_path);
 
     let updated = {
         let mut dao = exif_dao.lock().expect("Unable to lock ExifDao");