Sandbox Environment

[wavehassman]

Changes

Adds a fully automated ephemeral sandbox environment for final validation before merging develop → multitenancy.

How it works

• Spin-up: triggers on a PR to multitenancy, pauses for approval from designated reviewers (via GitHub environment protection, current just me and Chris), then spins up the full stack
• Tear-down: fires automatically when the PR is merged into multitenancy
• Only one sandbox can exist at a time this is enforced by a concurrency group and a fail-fast existence check at the start of the workflow

DISCLAIMER: I have no clue how to test this since it all works through git hub actions help

Checklist

It can be helpful to check the Checks and Files changed tabs.
Please review the contributor guide and reach out to your Tech Lead if anything is unclear.
Please request reviewers and ping on slack only after you've gone through this whole checklist.

• All commits are tagged with the ticket number
• No linting errors / newline at end of file warnings
• All code follows repository-configured prettier formatting
• No merge conflicts
• All checks passing
• Screenshots of UI changes (see Screenshots section)
• Remove any non-applicable sections of this template
• Assign the PR to yourself
• No yarn.lock changes (unless dependencies have changed)
• Request reviewers & ping on Slack
• PR is linked to the ticket (fill in the closes line below)