fix(docker): upgrade Compose v2.40.3 → v5.1.1 to remediate dependency CVEs (#283)

Compose v2.40.3 was compiled with Go 1.24.9, grpc 1.74.2, and
x/crypto 0.38.0 — all below the minimum safe versions identified
in the March 2026 security audit. Upgrading to v5.1.1 (Go 1.25.8,
x/crypto 0.46.0) resolves CVE-2025-68121, CVE-2025-61726,
CVE-2025-61729, CVE-2026-25679, and CVE-2025-47913.

CVE-2026-33186 (grpc ≥1.79.3) remains unresolved — no upstream
Docker CLI or Compose release includes grpc past 1.78.0 yet.

CVE-2026-33671 (picomatch) and CVE-2026-33747/33748 (buildkit) were
already patched in prior releases.

docs/docs.json

@@ -107,7 +107,8 @@
       {
         "group": "Reference",
         "pages": [
-          "reference/settings"
+          "reference/settings",
+          "reference/security-advisories"
         ]
       },
       {