Malformed and throwing protocol frames are dropped instead of crashing the client

Worker control responses with a non-string or unrecognized error now produce a described Error instead of Error(undefined). A new wrapper catches exceptions thrown by frame handlers, logs the dropped frame's type and subtype, and continues; the SDK/sessions client routes every delivery through it and reports remote_connect_frame_handler_threw telemetry when a handler throws. Thin-client control replies are now validated against their zod schema, returning null and logging the first schema issue instead of trusting the payload, and history prefetch wraps per-frame conversion in try/catch, skipping frames that fail.