- Added shared JS runtime infrastructure with RuntimeHooks, RuntimeOptions, JsRuntime, and indirectEval-based execution. - Reworked worker execution to use runtime.run, track active runs, and clean pending tool calls on close. - Added tool-call and tool-reply message variants and wired supervisor/worker to route run-scoped calls. - Added shared helper globals (read, writeFile, diff, tree, env) for browser-tab JS execution.