chore(readme): refresh demo GIFs from docs, lead with Mothership (#4878) #18154

Job	Run time
Detect Version	3s
Test and Build / Test and Build	5m 19s
Check Docs Changes	0s
Build Dev ECR	0s
Build ARM64 (GHCR Only)	0s
Migrate Dev DB	-1s
Build AMD64 (./docker/db.Dockerfile, ghcr.io/simstudioai/migrations, ECR_MIGRATIONS)	58s
Build AMD64 (./docker/app.Dockerfile, ghcr.io/simstudioai/simstudio, ECR_APP)	3m 32s
Build AMD64 (./docker/realtime.Dockerfile, ghcr.io/simstudioai/realtime, ECR_REALTIME)	49s
Create GHCR Manifests	0s
Process Docs	0s
Create GitHub Release	0s
	10m 40s

Provide feedback