fix: include files without EXIF when sorting by date

Date sorting previously used a DB-level query that acted as an inner join,
silently dropping files with no image_exif row. Replace it with the existing
in-memory sort which already falls back to filename-extracted and filesystem
dates, so all files appear in sorted results.

Also removes the now-unused get_files_sorted_by_date trait method and its
SqliteExifDao implementation and test mock.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/files.rs

@@ -61,45 +61,19 @@ fn apply_sorting_with_exif(
 
     match sort_type {
         SortType::DateTakenAsc | SortType::DateTakenDesc => {
-            info!("Date sorting requested, using database-level sorting");
-
-            // Collect file paths for batch EXIF query
-            let file_paths: Vec<String> = files.iter().map(|f| f.file_name.clone()).collect();
-
-            // Try database-level sorting first (most efficient)
-            let ascending = sort_type == SortType::DateTakenAsc;
-            match exif_dao.get_files_sorted_by_date(
+            info!("Date sorting requested, using in-memory sort with EXIF/filename fallback");
+            // Use in-memory sort so files without EXIF dates are included via
+            // filename extraction and filesystem metadata fallbacks.
+            let (sorted, _) = in_memory_date_sort(
+                files,
+                sort_type,
+                exif_dao,
                 span_context,
-                &file_paths,
-                ascending,
+                base_path,
                 limit,
                 offset,
-            ) {
-                Ok((sorted_files, db_total)) => {
-                    info!(
-                        "Database-level date sorting succeeded, returned {} files",
-                        sorted_files.len()
-                    );
-                    (sorted_files, db_total)
-                }
-                Err(e) => {
-                    warn!(
-                        "Database-level sorting failed: {:?}, falling back to in-memory sort",
-                        e
-                    );
-                    // Fallback to in-memory sorting with date extraction
-                    let (sorted, _) = in_memory_date_sort(
-                        files,
-                        sort_type,
-                        exif_dao,
-                        span_context,
-                        base_path,
-                        limit,
-                        offset,
-                    );
-                    (sorted, total_count)
-                }
-            }
+            );
+            (sorted, total_count)
         }
         _ => {
             // Use regular sort for non-date sorting
@@ -1352,19 +1326,6 @@ mod tests {
             Ok(Vec::new())
         }
 
-        fn get_files_sorted_by_date(
-            &mut self,
-            _context: &opentelemetry::Context,
-            file_paths: &[String],
-            _ascending: bool,
-            _limit: Option<i64>,
-            _offset: i64,
-        ) -> Result<(Vec<String>, i64), DbError> {
-            // For tests, just return all files unsorted
-            let count = file_paths.len() as i64;
-            Ok((file_paths.to_vec(), count))
-        }
-
         fn get_all_with_gps(
             &mut self,
             _context: &opentelemetry::Context,