docs: publish Tend Compose continuity evidence

Export the reviewed allowlisted snapshot from private source commit 07c1655921f21ee5e4fc4d85639d199e8867b17d. This records the Docker Compose activation, schema-compatible rollback, and stateful migration resource findings from Observatory Preview 19 dogfooding.

AI-Assisted: OpenAI Codex
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

internal/deploy/lock_linux_test.go

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+//go:build linux
+
+package deploy
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestHostWideLockSerializesIndependentServices(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "tend-deploy.lock")
+	first, err := acquireLock(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer first.Close()
+	if second, err := acquireLock(path); err == nil {
+		_ = second.Close()
+		t.Fatal("second service acquired the shared activation lock")
+	}
+	if err = first.Close(); err != nil {
+		t.Fatal(err)
+	}
+	third, err := acquireLock(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_ = third.Close()
+}