refactor: reorganize, add package (opencode, osgrep, beads), add ai agent shell

modules/home/programs/helix.nix

@@ -0,0 +1,27 @@
+{ pkgs, lib, ... }: {
+  programs.helix = {
+    enable = lib.mkDefault true;
+    settings = {
+      theme = "gruber-darker";
+      editor = {
+        auto-save = {
+          focus-lost = true;
+          after-delay = {
+            enable = true;
+            timeout = 3000;
+          };
+        };
+        cursor-shape = {
+          normal = "block";
+          insert = "bar";
+          select = "underline";
+        };
+      };
+    };
+    languages.language = [{
+      name = "nix";
+      auto-format = true;
+      formatter.command = "${pkgs.nixfmt-classic}/bin/nixfmt";
+    }];
+  };
+}