Bump forge-demo hello copy for Phase 5 release

Goal

Small web-service change: update the forge-demo hello copy to the Phase 5 release message, recorded as the Phase 5 asciinema demo of the factory flow (task → worker PR → review → merge → Argo).

Acceptance criteria

• PR opened against main that changes k8s/apps/forge-demo-hello hello-html copy
• Review checklist completed before merge
• After merge, Argo Application forge-demo-hello Healthy/Synced
• curl -fsS https://localpower.diegobarahona.com | grep -q "Phase 5"