docs(vscode): add AGENTS.md rule to prefer kilo-ui styles over custom CSS (#475)

packages/kilo-vscode/AGENTS.md

@@ -85,6 +85,7 @@ New webview features must use **`@kilocode/kilo-ui`** components instead of raw
 - New CSS for components not yet in kilo-ui goes into `chat.css` grouped by comment-delimited sections (`/* Component Name */`). Once a kilo-ui equivalent exists, remove the section.
 - **Check the desktop app first**: [`packages/app/src/`](../../packages/app/src/) is the reference implementation for how kilo-ui components are composed together. Always check how the app uses a component before implementing it in the webview — don't just look at the component API in isolation.
 - **`data-component` and `data-slot` attributes carry CSS styling** — kilo-ui uses `[data-component]` and `[data-slot]` attribute selectors, not class names. When the app uses e.g. `data-component="permission-prompt"` and `data-slot="permission-actions"`, these get kilo-ui styling for free.
+- **Prefer kilo-ui styles**: Always reuse existing kilo-ui CSS variables, tokens, and component styles instead of writing custom CSS. If a style doesn't exist in kilo-ui yet, add it there and reuse it rather than inlining or duplicating styles in the webview.
 - **Icons**: kilo-ui has 75+ custom SVG icons in [`packages/ui/src/components/icon.tsx`](../../packages/ui/src/components/icon.tsx). To list all available icon names: `node -e "const c=require('fs').readFileSync('../../packages/ui/src/components/icon.tsx','utf8');[...c.matchAll(/^\\s{2}[\"']?([\\w-]+)[\"']?:\\s*\x60/gm)].map(m=>m[1]).sort().forEach(n=>console.log(n))"`. Icon names use both hyphenated (`arrow-left`) and bare-word (`brain`, `console`, `providers`) keys.
 
 ## Debugging