add inputs to specialArgs and make templates use it.

templates/clan/flake-parts/modules/shared.nix

@@ -1,7 +1,14 @@
-{ clan-core, ... }:
+{
+  clan-core,
+  # Optional, if you want to access other flakes:
+  # self,
+  ...
+}:
 {
   imports = [
     clan-core.clanModules.sshd
     clan-core.clanModules.root-password
+    # You can access other flakes imported in your flake via `self` like this:
+    # self.inputs.nix-index-database.nixosModules.nix-index
   ];
 }