chore: drop unused Server.capabilities() helper

Added earlier in this branch for ServerRunner._handle_initialize, which
now reads from InitializationOptions instead. No callers remain.

Author: maxisbey

src/mcp/server/lowlevel/server.py

@@ -307,10 +307,6 @@ def get_notification_handler(self, method: str) -> HandlerEntry[LifespanResultT]
         """Return the registered entry for a notification method, or `None`."""
         return self._notification_handlers.get(method)
 
-    def capabilities(self) -> types.ServerCapabilities:
-        """Derive `ServerCapabilities` from registered handlers and constructor options."""
-        return self.get_capabilities(self._notification_options, self._experimental_capabilities)
-
     # TODO: Rethink capabilities API. Currently capabilities are derived from registered
     # handlers but require NotificationOptions to be passed externally for list_changed
     # flags, and experimental_capabilities as a separate dict. Consider deriving capabilities