fix(api): sync REST API download endpoint with updated dl command (#98)

The REST API download endpoint was broken after recent dl command changes.

- Add missing vbitrate_range, abitrate_range, and worst parameters to the API call and DEFAULT_DOWNLOAD_PARAMS
- Convert wanted episode strings (S01E01) to internal SxE format via SeasonRange so episode filtering works correctly
- Track completed output files via dl.completed_files instead of returning an empty list

Closes #98

pyproject.toml

@@ -66,6 +66,7 @@ dependencies = [
     "wasmtime>=41.0.0",
     "animeapi-py>=0.6.0",
     "rnet>=2.4.2",
+    "bandit>=1.9.4",
 ]
 
 [project.urls]