feat(zed): add Nord theme and project settings

Theme file lives in .zed/nord.json; arty zed:theme:install copies it
to the Windows Zed themes directory via wslpath.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.zed/settings.json

@@ -0,0 +1,7 @@
+{
+  "theme": {
+    "mode": "system",
+    "dark": "Nord",
+    "light": "Nord"
+  }
+}