Tools running inside a ToolNode can already read the current graph state
via `getCurrentTaskInput()`, but this was not documented as a
first-class option and the browser-safe variant (passing config
explicitly) was not surfaced.
This adds:
- JSDoc on getCurrentTaskInput documenting the optional config arg and
browser usage
- A ToolNode JSDoc example showing how tools access graph state and
runtime context
- Browser-safe guidance in the agents context docs and the
pass-run-time-values-to-tools how-to (`getCurrentTaskInput(config)`)
- A regression test verifying a ToolNode tool can read graph state via
getCurrentTaskInput(config)
Closes#2506
Christian Bromann
ef04db316d