Refactor: Remove unused Whisper variants

This commit removes the `whisper_variant` and `whisper_hotwords_variant`
fields from the `run_id` generation and the `print_meta_summary`
function.

These variants are no longer used as the project is shifting focus to
LLM-based generation. The `run_full_case.rs` example has also been
updated to reflect this change.

server/tests/common/users.rs

@@ -33,7 +33,7 @@ pub fn test_user(slug: &str) -> User {
         api_key: format!("key-{slug}"),
         web_password: hash_password(TEST_PASSWORD),
         role: "doctor".into(),
-        whisper: Default::default(),
+        language: None,
         retention: Default::default(),
         window_hours: 72,
         preview_lines: 2,