Enable OpenCode Zen for minimax + kimi; add buffbench agents #6509

Job	Run time
build-and-check	2m 54s
test-integration-packages/internal	1m 1s
test-integration-packages/billing	1m 6s
test-integration-cli	48s
test-integration-packages/agent-runtime	52s
test-integration-sdk	1m 13s
test-integration-common	40s
test-.agents	42s
test-integration-web	43s
test-web	2m 57s
test-cli	53s
test-common	46s
test-packages/agent-runtime	51s
test-packages/billing	46s
test-packages/internal	52s
test-sdk	53s
	17m 57s

Provide feedback