removed agenix

modules/core/matrix-secret.nix

@@ -0,0 +1,27 @@
+{ config, pkgs, lib, ... }:
+
+{
+  # ── Generate Matrix registration secret at runtime ──────────
+  systemd.services.matrix-synapse-secret-init = {
+    description = "Generate Matrix Synapse registration secret if missing";
+    wantedBy = [ "multi-user.target" ];
+    before = [ "matrix-synapse.service" ];
+    serviceConfig = {
+      Type = "oneshot";
+      RemainAfterExit = true;
+    };
+    path = [ pkgs.pwgen pkgs.coreutils ];
+    script = ''
+      SECRET_FILE="/var/lib/matrix-synapse/registration-secret"
+      if [ ! -f "$SECRET_FILE" ]; then
+        mkdir -p /var/lib/matrix-synapse
+        pwgen -s 64 1 > "$SECRET_FILE"
+        chown matrix-synapse:matrix-synapse "$SECRET_FILE"
+        chmod 600 "$SECRET_FILE"
+        echo "Generated Matrix registration secret"
+      else
+        echo "Matrix registration secret already exists, skipping"
+      fi
+    '';
+  };
+}