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/serverpolicy/ownership_linux.go

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+//go:build linux
+
+package serverpolicy
+
+import (
+	"os"
+	"syscall"
+)
+
+func rootOwned(info os.FileInfo) bool {
+	stat, ok := info.Sys().(*syscall.Stat_t)
+	return ok && stat.Uid == 0
+}