feat(claude): add caveman and oh-my-claudecode skills via flake inputs

Declaratively manage Claude Code skills through home-manager by fetching
plugin repos as non-flake inputs and symlinking their skills directories.

home.nix

@@ -1,4 +1,4 @@
-{ config, pkgs, lib, ... }:
+{ config, pkgs, lib, caveman, oh-my-claudecode, ... }:
 
 {
   home.username = "l-wyatt";
@@ -207,6 +207,20 @@
   # Use kickstart.nvim configuration from flake
   programs.neovim-kickstart.enable = true;
 
+  # Claude Code skills (managed declaratively via flake inputs)
+  home.file.".claude/skills/caveman" = {
+    source = "${caveman}/skills/caveman";
+    recursive = true;
+  };
+  home.file.".claude/skills/caveman-help" = {
+    source = "${caveman}/skills/caveman-help";
+    recursive = true;
+  };
+  home.file.".claude/skills/oh-my-claudecode" = {
+    source = "${oh-my-claudecode}/skills";
+    recursive = true;
+  };
+
   # Claude Code configuration
   home.file.".claude/CLAUDE.md" = {
     text = ''