Recreate Next.js source — shadcn components, chart, types, hooks

Source files were untracked and lost during reset. Recreated:
- page.tsx (full 3-tab dashboard), layout.tsx, globals.css (shadcn theme)
- types.ts, api.ts, utils.ts
- strategy-card.tsx, equity-chart.tsx, positions-panel.tsx
- ui/ (7 shadcn wrappers: card, badge, button, table, tabs, sheet, collapsible, select)
- Config files: next.config.ts, tsconfig.json, postcss.config.mjs, components.json

dashboard-next/src/components/ui/button.tsx

@@ -0,0 +1,37 @@
+import * as React from "react";
+import { cn } from "@/lib/utils";
+
+function Button({
+  className,
+  variant = "default",
+  size = "default",
+  ...props
+}: React.ComponentProps<"button"> & {
+  variant?: "default" | "ghost" | "outline";
+  size?: "default" | "sm" | "icon";
+}) {
+  const variants: Record<string, string> = {
+    default: "bg-primary text-primary-foreground hover:bg-primary/90",
+    ghost: "hover:bg-accent hover:text-accent-foreground",
+    outline: "border border-input bg-background hover:bg-accent hover:text-accent-foreground",
+  };
+  const sizes: Record<string, string> = {
+    default: "h-9 px-4 py-2",
+    sm: "h-8 rounded-md px-3 text-xs",
+    icon: "h-9 w-9",
+  };
+  return (
+    <button
+      data-slot="button"
+      className={cn(
+        "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0",
+        variants[variant],
+        sizes[size],
+        className,
+      )}
+      {...props}
+    />
+  );
+}
+
+export { Button };