refactor(db): port preview environments to sqlc (#77)

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>

app/backend/sqlc/queries/preview_environments.sql

@@ -0,0 +1,121 @@
+-- name: ListPreviewEnvironmentsForProject :many
+SELECT pe.id, pe.project_id, pe.service_id, pe.preview_service_id, pe.branch_name, pe.pr_number,
+       pe.environment, pe.status, pe.url, pe.expires_at, pe.created_at, pe.updated_at,
+       s.id AS svc_id, s.name AS service_name, s.type AS service_type
+FROM preview_environments pe
+LEFT JOIN services s ON pe.service_id = s.id
+WHERE pe.project_id = $1
+ORDER BY pe.created_at DESC;
+
+-- name: GetPreviewEnvironment :one
+SELECT pe.id, pe.project_id, pe.service_id, pe.preview_service_id, pe.branch_name, pe.pr_number,
+       pe.environment, pe.status, pe.url, pe.expires_at, pe.created_at, pe.updated_at,
+       s.id AS svc_id, s.name AS service_name, s.type AS service_type
+FROM preview_environments pe
+LEFT JOIN services s ON pe.service_id = s.id
+JOIN projects p ON pe.project_id = p.id
+WHERE pe.id = $1 AND (p.is_approved OR p.owner_id = $2 OR $3::bool
+    OR EXISTS (SELECT 1 FROM project_members pm WHERE pm.project_id = p.id AND pm.user_id = $2));
+
+-- name: GetPreviewEnvironmentForWrite :one
+SELECT pe.id, pe.project_id, pe.service_id, pe.branch_name, pe.pr_number,
+       pe.environment, pe.status, pe.url, pe.expires_at, pe.created_at, pe.updated_at
+FROM preview_environments pe
+JOIN projects p ON pe.project_id = p.id
+WHERE pe.id = $1 AND (p.owner_id = $2 OR $3::bool);
+
+-- name: GetPreviewEnvironmentForPromote :one
+SELECT pe.id, pe.project_id, pe.service_id, pe.preview_service_id, pe.branch_name, pe.environment, pe.status
+FROM preview_environments pe
+JOIN projects p ON pe.project_id = p.id
+WHERE pe.id = $1 AND (p.owner_id = $2 OR $3::bool);
+
+-- name: GetPreviewEnvironmentOwner :one
+SELECT p.owner_id
+FROM preview_environments pe
+JOIN projects p ON pe.project_id = p.id
+WHERE pe.id = $1;
+
+-- name: GetPreviewServiceID :one
+SELECT preview_service_id FROM preview_environments WHERE id = $1;
+
+-- name: UpdatePreviewEnvironment :exec
+UPDATE preview_environments
+SET status = $1, url = $2, expires_at = $3, updated_at = $4
+WHERE id = $5;
+
+-- name: MarkPreviewEnvironmentStatus :exec
+UPDATE preview_environments SET status = $1, updated_at = NOW() WHERE id = $2;
+
+-- name: DeletePreviewEnvironment :exec
+DELETE FROM preview_environments WHERE id = $1;
+
+-- name: CountActivePreviewsForBranch :one
+SELECT COUNT(*) FROM preview_environments
+WHERE service_id = $1 AND branch_name = $2 AND status NOT IN ('expired', 'stopped');
+
+-- name: CreatePreviewEnvironment :exec
+INSERT INTO preview_environments
+    (id, project_id, service_id, preview_service_id, branch_name, pr_number, environment,
+     status, url, expires_at, created_at, updated_at)
+VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12);
+
+-- name: UpdateServicePreviewBranch :exec
+UPDATE services SET git_branch = $1, domain = '', updated_at = NOW() WHERE id = $2;
+
+-- name: DeleteAllServiceDomains :exec
+DELETE FROM service_domains WHERE service_id = $1;
+
+-- name: CreatePreviewDomain :exec
+INSERT INTO service_domains (service_id, domain, is_default, cert_type) VALUES ($1, $2, true, 'tls');
+
+-- name: InsertPendingDeployment :exec
+INSERT INTO deployments (id, service_id, version, commit_hash, status, created_at, updated_at)
+VALUES ($1, $2, $3, $4, 'pending', NOW(), NOW());
+
+-- name: ListExpiredPreviewsForUser :many
+SELECT pe.id, pe.project_id, pe.service_id, pe.preview_service_id, pe.branch_name, pe.environment
+FROM preview_environments pe
+JOIN projects p ON pe.project_id = p.id
+WHERE (p.owner_id = $1 OR $2::bool) AND pe.expires_at < NOW() AND pe.status != 'expired';
+
+-- name: ListSweepablePreviews :many
+SELECT id, preview_service_id FROM preview_environments
+WHERE expires_at < NOW() AND status NOT IN ('expired', 'stopped');
+
+-- name: SyncPreviewStatuses :exec
+UPDATE preview_environments pe
+SET status = derived.st, updated_at = NOW()
+FROM (
+    SELECT pe2.id,
+        CASE
+            WHEN s.status IN ('running', 'deployed') THEN 'running'
+            WHEN s.status IN ('failed', 'error') THEN 'failed'
+            WHEN s.status IN ('building', 'deploying', 'queued', 'pending', 'cloning') THEN 'building'
+            ELSE pe2.status
+        END AS st
+    FROM preview_environments pe2
+    JOIN services s ON pe2.preview_service_id = s.id
+) derived
+WHERE pe.id = derived.id
+  AND pe.status IN ('building', 'running', 'failed')
+  AND pe.status <> derived.st;
+
+-- name: GetProjectBrief :one
+SELECT id, name, owner_id FROM projects WHERE id = $1;
+
+-- name: GetServiceTypeBrief :one
+SELECT id, name, COALESCE(type, service_type, '') AS service_type FROM services WHERE id = $1 AND project_id = $2;
+
+-- name: GetServiceForDeploy :one
+SELECT s.id, s.project_id, s.name, s.type, s.status, s.image, s.command,
+       s.environment, s.git_repo, s.git_branch, s.build_path, s.cpu, s.memory,
+       COALESCE(s.replicas, 1) AS replicas, COALESCE(s.port, 0) AS port,
+       COALESCE(s.domain, '') AS domain, COALESCE(s.healthcheck_path, '') AS healthcheck_path,
+       COALESCE(s.restart_policy, 'unless-stopped') AS restart_policy,
+       COALESCE(s.builder, 'auto') AS builder, COALESCE(s.cpu_reserve, '') AS cpu_reserve,
+       COALESCE(s.memory_reserve, '') AS memory_reserve, COALESCE(s.static_build_cmd, '') AS static_build_cmd,
+       COALESCE(s.static_dir, '') AS static_dir,
+       s.created_at, s.updated_at
+FROM services s
+WHERE s.id = $1;