Tranche 3: all 30 raw sites in preview_environments.go — list/detail
joins, access-check reads, create/update/delete, promote, user cleanup,
TTL sweep, and the status-sync UPDATE...FROM CASE. Deployments and
preview_environments schema.sql definitions completed to match runtime.
Shared mapper converts generated rows to the PreviewEnvironment DTO;
DeleteServiceByID from tranche 2 is reused for clone teardown.
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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
