Rename on_this_day to memory_date with exclude-same-year behavior

Renamed the date filter parameter and changed default behavior to match
Google Photos memories - now excludes assets from the same year as the
reference date, returning only photos from previous years on that day.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

custom_components/immich_album_watcher/translations/en.json

@@ -175,9 +175,9 @@
                     "name": "Maximum Date",
                     "description": "Filter assets created on or before this date (ISO 8601 format)."
                 },
-                "on_this_day": {
-                    "name": "On This Day",
-                    "description": "Filter assets by matching month and day (memories/anniversary filter)."
+                "memory_date": {
+                    "name": "Memory Date",
+                    "description": "Filter assets by matching month and day, excluding the same year (memories filter)."
                 },
                 "city": {
                     "name": "City",