* fix(#2798): add regression test — context_window key already in VALID_CONFIG_KEYS
context_window was already added to both VALID_CONFIG_KEYS allowlists
(CJS and SDK) in a prior fix. The regression test confirms it stays there
and that config-set context_window succeeds end-to-end.
Regression test: tests/bug-2798-context-window-config-key.test.cjs
* fix(#2798): address CodeRabbit — add bash language to release notes fence
