Document the critical requirement to set COMPOSE_PROJECT_NAME for
worktree isolation:
- Problem: Without COMPOSE_PROJECT_NAME, all worktrees share image
names (e.g., test-price-db:latest) causing build conflicts
- Solution: export COMPOSE_PROJECT_NAME="test-${TEST_INSTANCE_ID}"
- Cleanup scoping: Only remove containers for current branch
Also updated:
- Common Mistakes table with new isolation pitfalls
- Service Test Script Template with COMPOSE_PROJECT_NAME export