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/appbackup/r640_complete_test.go

@@ -0,0 +1,53 @@
+package appbackup
+
+import (
+	"compress/gzip"
+	"errors"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// R-640: CheckDumpComplete reads the END of the copy. pg_dump 17.6+ prints `\unrestrict <key>` after
+// its marker, so the marker need not be the last line.
+func TestR640_CheckDumpComplete(t *testing.T) {
+	dir := t.TempDir()
+	big := make([]byte, 200*1024) // longer than the kept tail: the marker must be found at the END
+	for i := range big {
+		big[i] = 'x'
+	}
+	cases := []struct {
+		name, body string
+		t          DBType
+		gz, ok     bool
+	}{
+		{"pg complete", "-- PostgreSQL database dump\nCOPY t FROM stdin;\n1\n\\.\n\n--\n-- PostgreSQL database dump complete\n--\n\n\\unrestrict abc\n", DBTypePostgres, false, true},
+		{"pg cut inside COPY", "-- PostgreSQL database dump\nCOPY t FROM stdin;\n1\n", DBTypePostgres, false, false},
+		{"pg marker only at the start is not an end", "-- PostgreSQL database dump complete\n" + string(big) + "\n", DBTypePostgres, false, false},
+		{"pg complete, gzipped", "-- PostgreSQL database dump\n" + string(big) + "\n-- PostgreSQL database dump complete\n", DBTypePostgres, true, true},
+		{"pg cut, gzipped", "-- PostgreSQL database dump\n" + string(big), DBTypePostgres, true, false},
+		{"mariadb complete", "-- MariaDB dump 10.19\nINSERT INTO `t` VALUES (1);\n-- Dump completed on 2026-09-23\n", DBTypeMariaDB, false, true},
+		{"mariadb cut", "-- MariaDB dump 10.19\nINSERT INTO `t` VALUES (1),(2", DBTypeMariaDB, false, false},
+		{"unknown engine never passes", "anything\n-- Dump completed\n", DBType("sqlite"), false, false},
+	}
+	for i, c := range cases {
+		p := filepath.Join(dir, "d"+string(rune('a'+i))+".sql")
+		if c.gz {
+			p += ".gz"
+			f, _ := os.Create(p)
+			w := gzip.NewWriter(f)
+			w.Write([]byte(c.body))
+			w.Close()
+			f.Close()
+		} else if err := os.WriteFile(p, []byte(c.body), 0o644); err != nil {
+			t.Fatal(err)
+		}
+		err := CheckDumpComplete(p, c.t)
+		if (err == nil) != c.ok {
+			t.Errorf("%s: ok=%v, got err=%v", c.name, c.ok, err)
+		}
+		if !c.ok && c.t != "sqlite" && !errors.Is(err, ErrDumpIncomplete) {
+			t.Errorf("%s: want ErrDumpIncomplete, got %v", c.name, err)
+		}
+	}
+}