P9-7: Test deployment process

[umwelt]

Estimated: 3h
Dependencies: P9-1, P9-2, P9-5

Acceptance Criteria

• Full deployment to TestFlight
• Full deployment to Play Store internal testing
• End-to-end deployment process documented
• Rollback procedure tested
• Version numbering incremented correctly
• Release notes included
• No deployment errors

Tests

• Deployment succeeds to TestFlight
• Deployment succeeds to Play internal
• App installable from stores
• Rollback works