Propagate terminal write errors from the chat prompt and explicitly ignore stream close errors during cleanup.
Update chat tests to assert response writer errors so errcheck passes without hiding failed writes.
Tests:
- go test -count=1 ./core/cli/chat
- go test -count=1 ./core/cli
Assisted-by: Codex:GPT-5
Signed-off-by: Ching Kao <0980124jim@gmail.com>