fix: set ANTHROPIC_API_KEY from agenix secret for Claude Code (#368)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: stackptr

home/secrets/claude-code-api-key.age

@@ -2,4 +2,5 @@ let
   keys = with (import ../keys.nix); [home Rhizome];
 in {
   "home/secrets/aichat-env.age".publicKeys = keys;
+  "home/secrets/claude-code-api-key.age".publicKeys = keys;
 }

lib/secrets/home.nix

@@ -27,6 +27,14 @@ in {
 
   config = lib.mkMerge [
     (mkIf cfg.ai.enable {
+      age.secrets.claude-code-api-key = {
+        file = ../../home/secrets/claude-code-api-key.age;
+      };
+
+      programs.zsh.initExtra = ''
+        export ANTHROPIC_API_KEY="$(cat ${config.age.secrets.claude-code-api-key.path})"
+      '';
+
       programs.claude-code = {
         enable = true;
         memory.source = "${llm-profile}/README.md";