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.)

components/ui/label.tsx

@@ -1,19 +1,16 @@
 "use client";
 
-import * as LabelPrimitive from "@radix-ui/react-label";
-import type * as React from "react";
+import * as React from "react";
 
 import { cn } from "@/lib/utils";
 
-function Label({
-  className,
-  ...props
-}: React.ComponentProps<typeof LabelPrimitive.Root>) {
+function Label({ className, ...props }: React.ComponentProps<"label">) {
   return (
-    <LabelPrimitive.Root
+    // oxlint-disable-next-line jsx_a11y/label-has-associated-control
+    <label
       data-slot="label"
       className={cn(
-        "flex select-none items-center gap-2 font-medium text-sm leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-50 group-data-[disabled=true]:pointer-events-none group-data-[disabled=true]:opacity-50",
+        "flex items-center gap-2 text-sm leading-none font-medium select-none group-data-[disabled=true]:pointer-events-none group-data-[disabled=true]:opacity-50 peer-disabled:cursor-not-allowed peer-disabled:opacity-50",
         className,
       )}
       {...props}