chore: apply cargo fmt across workspace and update docs

- Run cargo fmt on all Rust crates for consistent formatting
- Update CLAUDE.md with WASM plugin commands and dev.ps1 instructions
- Update wiki: add WASM plugin architecture, rewrite dev environment docs
- Minor frontend cleanup (unused imports)

apps/web/src/pages/settings/ThemeSettings.tsx

@@ -3,14 +3,13 @@ import { Form, Input, Select, Button, ColorPicker, message, Typography } from 'a
 import {
   getTheme,
   updateTheme,
-  type ThemeConfig,
 } from '../../api/themes';
 
 // --- Component ---
 
 export default function ThemeSettings() {
   const [form] = Form.useForm();
-  const [loading, setLoading] = useState(false);
+  const [, setLoading] = useState(false);
   const [saving, setSaving] = useState(false);
 
   const fetchTheme = useCallback(async () => {