refactor(db): port cron jobs to sqlc (#80)

Tranche 6 — 15 of 17 raw sites in cron.go. Adds cron_jobs and
cron_executions to schema.sql and a full query set: job CRUD, owner
joins (via project and via service), execution list/insert/finish,
due-job scan for the scheduler, run bookkeeping, and retention trim.

The filtered list query and the sparse UPDATE builder stay raw — both
are genuinely dynamic. Go models keep string IDs; cronJobFrom and
cronExecutionFrom map uuid/null types at the boundary.

TestCronLiveInvariants covers insert/read, both owner joins, the
trigger read, execution lifecycle, retention trim, and delete on live
Postgres.

Generated with [Devin](https://devin.ai)

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/backend/internal/api/cron_test.go

@@ -1,9 +1,16 @@
 package api
 
 import (
+	"context"
+	"database/sql"
 	"strings"
 	"testing"
 	"time"
+
+	"containr/internal/database"
+	"containr/internal/database/sqlcdb"
+
+	"github.com/google/uuid"
 )
 
 func TestCalculateNextRun(t *testing.T) {
@@ -64,3 +71,123 @@ func TestCalculateNextRunTimezone(t *testing.T) {
 		t.Logf("utc next: %v / tokyo next: %v", utcNext, tokyoNext)
 	}
 }
+
+// TestCronLiveInvariants exercises the cron.sql queries on live Postgres:
+// insert/read/owner join, execution lifecycle, run bookkeeping, retention trim.
+func TestCronLiveInvariants(t *testing.T) {
+	dsn := testDSNString(t)
+	db, err := database.NewConnection(dsn)
+	if err != nil {
+		t.Fatalf("connect: %v", err)
+	}
+	defer db.Close()
+	ctx := context.Background()
+	q := sqlcdb.New(db.DB)
+
+	userID := uuid.New()
+	projectID := uuid.New()
+	envID := uuid.New()
+	serviceID := uuid.New()
+	jobID := uuid.New()
+	suffix := strings.ReplaceAll(jobID.String()[:8], "-", "")
+	must := func(err error) {
+		t.Helper()
+		if err != nil {
+			t.Fatalf("setup: %v", err)
+		}
+	}
+	_, err = db.Exec(`INSERT INTO users (id, email, password_hash, name) VALUES ($1, $2, 'x', 'test')`,
+		userID, "cron-"+suffix+"@test.local")
+	must(err)
+	_, err = db.Exec(`INSERT INTO projects (id, name, owner_id, is_approved) VALUES ($1, $2, $3, true)`,
+		projectID, "cron-"+suffix, userID)
+	must(err)
+	_, err = db.Exec(`INSERT INTO environments (id, name, project_id) VALUES ($1, 'production', $2)`,
+		envID, projectID)
+	must(err)
+	_, err = db.Exec(`INSERT INTO services (id, name, project_id, environment_id, service_type, source_type)
+		VALUES ($1, $2, $3, $4, 'web', 'image')`,
+		serviceID, "cron-"+suffix, projectID, envID)
+	must(err)
+	defer func() { _, _ = db.Exec(`DELETE FROM users WHERE id = $1`, userID) }()
+
+	next, err := calculateNextRun("0 4 * * *", "UTC")
+	if err != nil {
+		t.Fatalf("schedule: %v", err)
+	}
+	must(q.InsertCronJob(ctx, sqlcdb.InsertCronJobParams{
+		ID: jobID, ProjectID: projectID, ServiceID: serviceID,
+		Name: "job-" + suffix, Schedule: "0 4 * * *", Command: "echo hi",
+		Timezone:  sql.NullString{String: "UTC", Valid: true},
+		Enabled:   sql.NullBool{Bool: true, Valid: true},
+		NextRunAt: ntPtr(next),
+	}))
+	job, err := q.GetCronJob(ctx, jobID)
+	if err != nil || job.Name != "job-"+suffix || job.Command != "echo hi" {
+		t.Fatalf("job: %v %+v", err, job)
+	}
+	owner, err := q.GetCronJobOwner(ctx, jobID)
+	if err != nil || owner != userID {
+		t.Fatalf("owner: %v %v", err, owner)
+	}
+	owner2, err := q.GetCronOwnerViaService(ctx, serviceID)
+	if err != nil || owner2 != userID {
+		t.Fatalf("owner via service: %v %v", err, owner2)
+	}
+	pid, err := q.GetCronJobProjectID(ctx, jobID)
+	if err != nil || pid != projectID {
+		t.Fatalf("project: %v %v", err, pid)
+	}
+
+	// Trigger-shaped read.
+	trig, err := q.GetCronJobForTrigger(ctx, jobID)
+	if err != nil || trig.ServiceID != serviceID || trig.OwnerID != userID {
+		t.Fatalf("trigger: %v %+v", err, trig)
+	}
+
+	// Execution lifecycle + retention trim.
+	for i := 0; i < 3; i++ {
+		execID := uuid.New()
+		must(q.InsertCronExecution(ctx, sqlcdb.InsertCronExecutionParams{
+			ID: execID, CronJobID: jobID,
+			StartedAt: time.Now().Add(time.Duration(i) * time.Second),
+			Status:    sql.NullString{String: "running", Valid: true},
+		}))
+		must(q.FinishCronExecution(ctx, sqlcdb.FinishCronExecutionParams{
+			FinishedAt: sql.NullTime{Time: time.Now(), Valid: true},
+			Status:     sql.NullString{String: "success", Valid: true},
+			Output:     sql.NullString{String: "ok", Valid: true},
+			Error:      sql.NullString{String: "", Valid: true},
+			ID:         execID,
+		}))
+	}
+	execs, err := q.ListCronExecutions(ctx, jobID)
+	if err != nil || len(execs) != 3 {
+		t.Fatalf("execs: %v %d", err, len(execs))
+	}
+	if execs[0].Status.String != "success" || !execs[0].FinishedAt.Valid {
+		t.Fatalf("exec row: %+v", execs[0])
+	}
+	must(q.TrimCronExecutions(ctx, sqlcdb.TrimCronExecutionsParams{CronJobID: jobID, Limit: 1}))
+	execs, _ = q.ListCronExecutions(ctx, jobID)
+	if len(execs) != 1 {
+		t.Fatalf("trim kept %d, want 1", len(execs))
+	}
+
+	must(q.UpdateCronJobRun(ctx, sqlcdb.UpdateCronJobRunParams{
+		LastRunAt:  sql.NullTime{Time: time.Now(), Valid: true},
+		LastStatus: sql.NullString{String: "success", Valid: true},
+		LastOutput: sql.NullString{String: "ok", Valid: true},
+		NextRunAt:  ntPtr(next),
+		ID:         jobID,
+	}))
+	job, _ = q.GetCronJob(ctx, jobID)
+	if job.LastStatus.String != "success" || !job.LastRunAt.Valid {
+		t.Fatalf("post-run job: %+v", job)
+	}
+
+	must(q.DeleteCronJob(ctx, jobID))
+	if _, err := q.GetCronJob(ctx, jobID); err == nil {
+		t.Fatal("deleted job still readable")
+	}
+}