feat: playlist shuffle, lazy resolution, TTS ducking, kept repair

Music:
- #random URL fragment shuffles playlist tracks before enqueuing
- Lazy playlist resolution: first 10 tracks resolve immediately,
  remaining are fetched in a background task
- !kept repair re-downloads kept tracks with missing local files
- !kept shows [MISSING] marker for tracks without local files
- TTS ducking: music ducks when merlin speaks via voice peer,
  smooth restore after TTS finishes

Performance (from profiling):
- Connection pool: preload_content=True for SOCKS connection reuse
- Pool tuning: 30 pools / 8 connections (up from 20/4)
- _PooledResponse wrapper for stdlib-compatible read interface
- Iterative _extract_videos (replace 51K-deep recursion with stack)
- proxy=False for local SearXNG

Voice + multi-bot:
- Per-bot voice config lookup ([<username>.voice] in TOML)
- Mute detection: skip duck silence when all users muted
- Autoplay shuffle deck (no repeats until full cycle)
- Seek clamp to track duration (prevent seek-past-end stall)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/alert.py

@@ -368,45 +368,56 @@ def _fetch_og_batch(urls: list[str]) -> dict[str, tuple[str, str, str]]:
 # -- YouTube InnerTube search (blocking) ------------------------------------
 
 def _extract_videos(obj: object, depth: int = 0) -> list[dict]:
-    """Recursively walk YouTube JSON to find video results.
+    """Walk YouTube JSON to find video results (iterative).
 
     Finds all objects containing both 'videoId' and 'title' keys.
     Resilient to YouTube rearranging wrapper layers.
+    Uses an explicit stack instead of recursion to avoid 50K+ call
+    overhead on deeply nested InnerTube responses.
     """
-    if depth > 20:
-        return []
-    results = []
-    if isinstance(obj, dict):
-        video_id = obj.get("videoId")
-        title_obj = obj.get("title")
-        if isinstance(video_id, str) and video_id and title_obj is not None:
-            if isinstance(title_obj, dict):
-                runs = title_obj.get("runs", [])
-                title = "".join(r.get("text", "") for r in runs if isinstance(r, dict))
-            elif isinstance(title_obj, str):
-                title = title_obj
-            else:
-                title = ""
-            if title:
-                # Extract relative publish time (e.g. "2 days ago")
-                pub_obj = obj.get("publishedTimeText")
-                date = ""
-                if isinstance(pub_obj, dict):
-                    date = pub_obj.get("simpleText", "")
-                elif isinstance(pub_obj, str):
-                    date = pub_obj
-                results.append({
-                    "id": video_id,
-                    "title": title,
-                    "url": f"https://www.youtube.com/watch?v={video_id}",
-                    "date": date,
-                    "extra": "",
-                })
-        for val in obj.values():
-            results.extend(_extract_videos(val, depth + 1))
-    elif isinstance(obj, list):
-        for item in obj:
-            results.extend(_extract_videos(item, depth + 1))
+    _MAX_DEPTH = 20
+    results: list[dict] = []
+    # Stack of (node, depth) tuples
+    stack: list[tuple[object, int]] = [(obj, 0)]
+    while stack:
+        node, d = stack.pop()
+        if d > _MAX_DEPTH:
+            continue
+        if isinstance(node, dict):
+            video_id = node.get("videoId")
+            title_obj = node.get("title")
+            if isinstance(video_id, str) and video_id and title_obj is not None:
+                if isinstance(title_obj, dict):
+                    runs = title_obj.get("runs", [])
+                    title = "".join(
+                        r.get("text", "") for r in runs if isinstance(r, dict)
+                    )
+                elif isinstance(title_obj, str):
+                    title = title_obj
+                else:
+                    title = ""
+                if title:
+                    pub_obj = node.get("publishedTimeText")
+                    date = ""
+                    if isinstance(pub_obj, dict):
+                        date = pub_obj.get("simpleText", "")
+                    elif isinstance(pub_obj, str):
+                        date = pub_obj
+                    results.append({
+                        "id": video_id,
+                        "title": title,
+                        "url": f"https://www.youtube.com/watch?v={video_id}",
+                        "date": date,
+                        "extra": "",
+                    })
+            # Reverse to preserve original traversal order (stack is LIFO)
+            children = [v for v in node.values() if isinstance(v, (dict, list))]
+            for val in reversed(children):
+                stack.append((val, d + 1))
+        elif isinstance(node, list):
+            for item in reversed(node):
+                if isinstance(item, (dict, list)):
+                    stack.append((item, d + 1))
     return results