M4 — channel browse + context-menu drill-down

Sidecar ChannelVideos op via rustypipe channel_videos(). Returns the
channel metadata block (id, name, subscribers, banner) alongside the
items array — same VideoItem shape as search.

Addon refactor: _add_video_items is now the shared listing builder.
Both _search_directory and _channel_directory call it. Each video
result gets a 'Go to <channel>' context-menu entry that
Container.Update's to ?action=channel&id=<channel_id> — so from any
search result, the user can drill into that channel's recent uploads
without going back through search.

Smoke verified on the Pi via Files.GetDirectory: LTT channel
(UCXuqSBlHAE6Xw-yeJA0Tunw) returned 30 recent videos.

Addon version 0.0.7.

sidecar/crates/torttube-sidecar/src/main.rs

@@ -50,6 +50,12 @@ enum Request {
         #[serde(default = "default_search_limit")]
         limit: u32,
     },
+    /// List a channel's recent videos. `id` is a YouTube channel ID (UC…).
+    ChannelVideos {
+        id: String,
+        #[serde(default = "default_search_limit")]
+        limit: u32,
+    },
 }
 
 fn default_search_limit() -> u32 {
@@ -163,6 +169,10 @@ async fn handle_line(line: &str) -> Response {
             Ok(v) => Response::ok(v),
             Err(e) => e.into(),
         },
+        Request::ChannelVideos { id, limit } => match resolve::channel_videos(&id, limit).await {
+            Ok(v) => Response::ok(v),
+            Err(e) => e.into(),
+        },
     }
 }
 

sidecar/crates/torttube-sidecar/src/resolve.rs

@@ -39,6 +39,43 @@ pub(crate) async fn search(query: &str, limit: u32) -> Result<Value, HandlerErro
     }))
 }
 
+/// List a channel's recent videos. Returns the same VideoItem shape as
+/// `search`, plus channel metadata (name, subscribers, description, banner).
+pub(crate) async fn channel_videos(channel_id: &str, limit: u32) -> Result<Value, HandlerError> {
+    use rustypipe::client::RustyPipe;
+
+    let rp = RustyPipe::new();
+    let ch = rp
+        .query()
+        .channel_videos(channel_id)
+        .await
+        .map_err(|e| classify_rustypipe_error(&e))?;
+
+    let items_json: Vec<Value> = ch
+        .content
+        .items
+        .iter()
+        .take(limit as usize)
+        .filter_map(|v| serde_json::to_value(v).ok())
+        .collect();
+
+    tracing::info!(channel_id, count = items_json.len(), "channel_videos ok");
+
+    Ok(serde_json::json!({
+        "source": "rustypipe",
+        "channel": {
+            "id": ch.id,
+            "name": ch.name,
+            "description": ch.description,
+            "subscribers": ch.subscriber_count,
+            "video_count": ch.video_count,
+            "avatar": ch.avatar,
+            "banner": ch.banner,
+        },
+        "items": items_json,
+    }))
+}
+
 /// DASH-ready resolve: returns rustypipe's full `video_only_streams` +
 /// `audio_streams` arrays + `details`. The Python addon builds an MPD
 /// from these and hands it to inputstream.adaptive — unlocks 1080p+ via