feat(sonarr): add a scrollable overview popup to series details

A series' overview renders as one line of a description box that does
not scroll, so a long overview overflows with no way to read the rest.
Pressing v on the series details Seasons tab now opens a popup holding
the full overview.

The popup owns its own ScrollableText, built fresh from the series'
overview when it opens and torn down on Esc so a reopened popup starts
at the top. Scrolling mutates only that owned state. The background
paragraph renders the Series record's overview, which carries no scroll
offset, so it cannot scroll along with the popup.

Cite the existing view keybinding from the series details context clues
and give the popup its own clue set so it does not inherit the hints of
the view underneath.

Enrich the shared series fixture to a multi-paragraph overview, and the
raw response fixture that encodes the same series, so a scrolled popup
is distinguishable from an unscrolled one.

src/network/sonarr_network/sonarr_network_test_utils.rs

@@ -19,7 +19,7 @@ pub mod test_utils {
         "title": "Test",
         "status": "continuing",
         "ended": false,
-        "overview": "Blah blah blah",
+        "overview": "Blah blah blah\r\n\r\nIt was filmed in Madison, Wisconsin: a city the crew never really left.\r\n\r\nThe first season took seven years to finish.\r\n",
         "network": "HBO",
         "seasons": [
             {
@@ -319,7 +319,14 @@ pub mod test_utils {
       title: "Test".to_owned().into(),
       status: SeriesStatus::Continuing,
       ended: false,
-      overview: Some("Blah blah blah".to_owned()),
+      overview: Some(
+        "Blah blah blah\r\n\
+         \r\n\
+         It was filmed in Madison, Wisconsin: a city the crew never really left.\r\n\
+         \r\n\
+         The first season took seven years to finish.\r\n"
+          .to_owned(),
+      ),
       network: Some("HBO".to_owned()),
       seasons: Some(vec![season()]),
       year: 2022,