Add interactive release search (M6)

Release listing and grab in the shared arr client, a full-screen release
list (sort, hide rejected, rejection reasons, confirmation before grabbing
rejected releases; Usenet only), and a season/episode picker for Sonarr.
Overlays are now a stack so dialogs can open above the release list.
Add a fake Newznab indexer to the dev setup.

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

internal/sonarr/sonarr.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"net/http"
 	"net/url"
+	"strconv"
 
 	"git.stinnesbeck.com/nils/arr-tui/internal/arr"
 )
@@ -166,3 +167,35 @@ func (c *Client) SearchSeries(ctx context.Context, seriesID int) error {
 func (c *Client) Queue(ctx context.Context) ([]arr.QueueItem, error) {
 	return c.QueueWith(ctx, url.Values{"includeSeries": {"true"}, "includeEpisode": {"true"}})
 }
+
+// Episode is an episode of a library series.
+type Episode struct {
+	ID            int    `json:"id"`
+	SeriesID      int    `json:"seriesId"`
+	SeasonNumber  int    `json:"seasonNumber"`
+	EpisodeNumber int    `json:"episodeNumber"`
+	Title         string `json:"title"`
+	AirDate       string `json:"airDate"`
+	HasFile       bool   `json:"hasFile"`
+	Monitored     bool   `json:"monitored"`
+}
+
+// Episodes lists all episodes of a library series.
+func (c *Client) Episodes(ctx context.Context, seriesID int) ([]Episode, error) {
+	var episodes []Episode
+	err := c.Do(ctx, http.MethodGet, "episode", url.Values{"seriesId": {strconv.Itoa(seriesID)}}, nil, &episodes)
+	return episodes, err
+}
+
+// EpisodeReleases runs an interactive search for one episode.
+func (c *Client) EpisodeReleases(ctx context.Context, episodeID int) ([]arr.Release, error) {
+	return c.Client.Releases(ctx, url.Values{"episodeId": {strconv.Itoa(episodeID)}})
+}
+
+// SeasonReleases runs an interactive search for a whole season (season packs and episodes).
+func (c *Client) SeasonReleases(ctx context.Context, seriesID, season int) ([]arr.Release, error) {
+	return c.Client.Releases(ctx, url.Values{
+		"seriesId":     {strconv.Itoa(seriesID)},
+		"seasonNumber": {strconv.Itoa(season)},
+	})
+}