feat(cockpit): aimock E2E harness — Phase 1 (streaming pilot, replaces legacy cockpit e2e) #907

Job	Run time
Cockpit — build / test	1m 45s
Cockpit — deploy smoke dry-run	1m 19s
Cockpit — representative capability smoke	1m 29s
Library — lint / test / build	3m 39s
Cockpit — secret-gated integration	1m 29s
examples/chat — python smoke	1m 23s
Website — lint / build	1m 49s
PostHog — dashboards-as-code drift check	1m 16s
Website — e2e	2m 25s
examples/chat — aimock e2e	2m 25s
Cockpit — build all examples	5m 9s
Cockpit — e2e	2m 15s
Deploy → Vercel	-1s
Production smoke	-1s
	26m 21s

Provide feedback