chore: add ECOSYSTEM.scm ecosystem metadata

Author: hyperpolymath

ECOSYSTEM.scm

@@ -0,0 +1,20 @@
+;; SPDX-License-Identifier: AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2025 Jonathan D.A. Jewell
+;; ECOSYSTEM.scm — sanctify-php
+
+(ecosystem
+  (version "1.0.0")
+  (name "sanctify-php")
+  (type "project")
+  (purpose "Haskell-based PHP hardening and security analysis tool.")
+
+  (position-in-ecosystem
+    "Part of hyperpolymath ecosystem. Follows RSR guidelines.")
+
+  (related-projects
+    (project (name "rhodium-standard-repositories")
+             (url "https://github.com/hyperpolymath/rhodium-standard-repositories")
+             (relationship "standard")))
+
+  (what-this-is "Haskell-based PHP hardening and security analysis tool.")
+  (what-this-is-not "- NOT exempt from RSR compliance"))