feat(readarr): show the author overview in the add author prompt

The add author confirmation popup previously left the space above the
root folder field blank. It now renders the selected search result's
overview there, in a fixed six line area matching the Radarr add movie
prompt, so the user can confirm they picked the right author before
adding. An author without an overview keeps the same layout.

The fully populated search result fixture gains a long overview so the
snapshot proves the paragraph is clipped to six lines.

src/models/servarr_data/readarr/readarr_data.rs

@@ -388,7 +388,19 @@ impl ReadarrData<'_> {
       foreign_author_id: "test-foreign-id".to_owned(),
       author_name: "Test Author".into(),
       status: AuthorStatus::Continuing,
-      overview: Some("some interesting description of the author".to_owned()),
+      overview: Some(
+        "Test Author is an American novelist whose science fiction has been translated into more \
+         than thirty languages. Born in a small river town, the author spent a decade as a marine \
+         biologist before turning to fiction, and the sea remains a constant presence in the work. \
+         The debut novel won several awards and introduced the sprawling shared universe that later \
+         books would return to again and again. Critics have praised the meticulous world building \
+         and the quiet, humane attention to ordinary people caught up in extraordinary events. The \
+         author also writes essays on the history of science, teaches an annual writing workshop, \
+         and lives with a large and opinionated cat. A new trilogy is currently in progress and is \
+         expected to conclude the long running saga that began with the first book. The final \
+         volume has already been announced for next year."
+          .to_owned(),
+      ),
       author_type: Some("Person".to_owned()),
       disambiguation: Some("American novelist".to_owned()),
       ratings: Some(Ratings {