controller v0.267.0: tests off DooPlex's Docker, cut-off copies refused, two pages true

R-650: internal/dockerexec — every docker exec routed through it; under
go test a real docker is refused (opt-in FELHOM_TEST_REAL_DOCKER=1; a stub
under the temp dir is allowed). api/stacks/web tests run under a silent
stub (TestMain). TestR650_NoBareDockerExec pins it repo-wide.
R-640: a dump without its engine's completion marker is refused before
the first mutation (unit + off-site restore) and again before any load.
R-499: the Tier-2 page's system-disk sentence has four true branches.
R-518: the backup button states the measured ~8 min stop.
R-626: measured on 9202, not reproduced.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/metrics/logscanner.go

@@ -3,8 +3,8 @@ package metrics
 import (
 	"context"
 	"fmt"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/dockerexec"
 	"log"
-	"os/exec"
 	"regexp"
 	"sort"
 	"strings"
@@ -98,7 +98,7 @@ func scanOneContainer(name string, since time.Duration, logger *log.Logger) Cont
 	defer cancel()
 
 	sinceStr := formatSinceDuration(since)
-	cmd := exec.CommandContext(ctx, "docker", "logs", "--since="+sinceStr, "--tail=1000", name)
+	cmd := dockerexec.CommandContext(ctx, "docker", "logs", "--since="+sinceStr, "--tail=1000", name)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		if logger != nil {
@@ -238,7 +238,7 @@ func FetchContainerLogTail(name string, tailLines int) (string, error) {
 	}
 	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
 	defer cancel()
-	cmd := exec.CommandContext(ctx, "docker", "logs", fmt.Sprintf("--tail=%d", tailLines), name)
+	cmd := dockerexec.CommandContext(ctx, "docker", "logs", fmt.Sprintf("--tail=%d", tailLines), name)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		return "", fmt.Errorf("docker logs %s: %w", name, err)