Add Sonarr client and series search/add flow (M3)

Sonarr client with lookup, add series (monitor modes) and search.
Refactor the movie view into a generic search view driven by a backend
interface so Movies and Series share one implementation.
Add F1-F4 / Alt+1-4 view switching that works while typing.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/ui/format_test.go

@@ -6,6 +6,7 @@ import (
 
 	"git.stinnesbeck.com/nils/arr-tui/internal/arr"
 	"git.stinnesbeck.com/nils/arr-tui/internal/radarr"
+	"git.stinnesbeck.com/nils/arr-tui/internal/sonarr"
 )
 
 func TestMovieLabel(t *testing.T) {
@@ -43,3 +44,45 @@ func TestDefaultIndexes(t *testing.T) {
 		t.Error("folderIndex")
 	}
 }
+
+func TestSeriesLabelAndDetails(t *testing.T) {
+	s := sonarr.Series{
+		Title: "Breaking Bad", Year: 2008, Network: "AMC", Status: "ended", Runtime: 47,
+		Genres:  []string{"Crime"},
+		Ratings: sonarr.Rating{Value: 9.3},
+		Seasons: []sonarr.Season{{SeasonNumber: 0}, {SeasonNumber: 1}},
+	}
+	if got := seriesLabel(s); got != "Breaking Bad (2008)" {
+		t.Errorf("label = %q", got)
+	}
+	got := seriesDetails(s)
+	for _, want := range []string{"Breaking Bad (2008)", "★ 9.3", "1 season ·", "47 min", "Network: AMC", "Status: ended"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("details missing %q:\n%s", want, got)
+		}
+	}
+
+	s.ID = 1
+	s.Statistics = sonarr.Statistics{EpisodeCount: 10, EpisodeFileCount: 4}
+	if got := seriesDetails(s); !strings.Contains(got, "4/10 episodes") {
+		t.Errorf("progress missing:\n%s", got)
+	}
+	s.Statistics.EpisodeFileCount = 10
+	if got := seriesDetails(s); !strings.Contains(got, "all episodes downloaded") {
+		t.Errorf("complete marker missing:\n%s", got)
+	}
+}
+
+func TestResultKeysAndWithID(t *testing.T) {
+	var r result = movieResult{radarr.Movie{TMDBID: 603, Title: "x"}}
+	if r.key() != "tmdb:603" || r.inLibrary() {
+		t.Fatalf("movie key/inLibrary: %q %v", r.key(), r.inLibrary())
+	}
+	if added := r.withID(5); !added.inLibrary() || r.inLibrary() {
+		t.Error("withID must return a flagged copy and leave the original alone")
+	}
+	r = seriesResult{sonarr.Series{TVDBID: 81189}}
+	if r.key() != "tvdb:81189" {
+		t.Errorf("series key = %q", r.key())
+	}
+}