chore: update dev config for nixpkgs-search

- Update .mcp.json to use nixpkgs-search options/packages servers
- Update CLAUDE.md example to use nixpkgs-search

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.mcp.json

@@ -1,15 +1,29 @@
 {
   "mcpServers": {
-    "nixos-options": {
+    "nixpkgs-options": {
       "command": "nix",
       "args": [
         "run",
-        ".",
+        ".#nixpkgs-search",
         "--",
+        "options",
         "serve"
       ],
       "env": {
-        "NIXOS_OPTIONS_DATABASE": "sqlite://:memory:"
+        "NIXPKGS_SEARCH_DATABASE": "sqlite://:memory:"
+      }
+    },
+    "nixpkgs-packages": {
+      "command": "nix",
+      "args": [
+        "run",
+        ".#nixpkgs-search",
+        "--",
+        "packages",
+        "serve"
+      ],
+      "env": {
+        "NIXPKGS_SEARCH_DATABASE": "sqlite://:memory:"
       }
     }
   }