refactor: migrate from Biome to oxlint/oxfmt, remove contact form

- Replace Biome with oxlint + oxfmt (OXC toolchain) for linting and formatting
- Add .oxlintrc.json and .oxfmtrc.json configuration files
- Update VS Code settings and devcontainer to use oxc-vscode extension
- Remove contact form, Resend email integration, and related server action/schema
- Remove unused UI components (accordion, alert, card, tabs, toggle, etc.)

lib/utils.ts

@@ -1,4 +1,4 @@
-import { type ClassValue, clsx } from "clsx";
+import { clsx, type ClassValue } from "clsx";
 import { twMerge } from "tailwind-merge";
 
 export function cn(...inputs: ClassValue[]) {