feat(search): search history bottom sheet

Record queries on explicit search and keep up to 100 entries.
Show them in a bottom sheet opened from the search bar, with
per-entry removal and clear-all.

README.md

@@ -21,6 +21,7 @@ The app stores dictionaries as DictZip files and builds compact binary indexes f
 ## Features
 
 - Fast headword search across multiple DSL dictionaries.
+- Search history in the empty search state: recent queries with per-entry removal and clear-all.
 - Import local `.dsl`, `.dsl.gz`, and `.dsl.dz` dictionary files.
 - Download dictionaries from configured URLs, with an optional `{DATE}` placeholder for dated releases.
 - Automatic extraction, DictZip compression, and indexing.