Reduce build and deploy times for faster feedback loops

[KOTungseth]

Description

Optimize build process for staging and production.

• Target staging builds to finish in minutes, not tens of minutes.
• Decouple contributor preview builds from production deploys.

Acceptance criteria

• Staging builds complete in minutes, not tens of minutes.
• Contributors can validate changes quickly before merging.
• Production deploy time is reduced or decoupled from contributor preview needs.