Add /live/browser/list_children OSC endpoint

Allows clients to explore the browser tree by category and path,
returning the names of child nodes at the given location.

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

AbletonOSC/browser.py

@@ -42,6 +42,9 @@ class BrowserHandler(AbletonOSCHandler):
         self._add("/live/browser/get/hotswap_target", self._get_hotswap_target)
         self._add("/live/browser/begin_hotswap", self._begin_hotswap)
 
+        # Path exploration
+        self._add("/live/browser/list_children", self._list_children)
+
     # ------------------------------------------------------------------
 
     def _browser(self):
@@ -118,6 +121,25 @@ class BrowserHandler(AbletonOSCHandler):
                 logger.warning("stop_preview: %s", e)
         return None
 
+    def _list_children(self, params: tuple) -> Optional[tuple]:
+        """List children at a browser path. params: category [, path_part, ...]"""
+        if not params:
+            return None
+        browser = self._browser()
+        if browser is None:
+            return None
+        category = str(params[0])
+        path = [str(p) for p in params[1:]]
+        try:
+            root = getattr(browser, category)
+            node = _iter_items(root, path) if path else root
+            if node is None:
+                return None
+            return tuple(child.name for child in node.children)
+        except Exception as e:
+            logger.warning("list_children %s/%s: %s", category, path, e)
+            return None
+
     def _get_hotswap_target(self, params: tuple) -> Optional[tuple]:
         browser = self._browser()
         if browser: