chore: add Biome for lint and fix all lint errors

- Install @biomejs/biome as devDependency at root
- Configure biome.json with 2-space indent, double quotes, Tailwind CSS support
- Add lint/lint:fix/format/format:fix scripts to root and app package.json
- Fix noNonNullAssertion: env vars extracted to variables with suppression, <div role=button> replaced with <button>
- Fix noUnusedVariables: remove unused destructured vars
- Fix useIterableCallbackReturn: arrow functions with block body
- Fix noExplicitAny: recharts Tooltip formatters
- Fix noLabelWithoutControl: add htmlFor+id or use <span> for non-input labels
- Fix noStaticElementInteractions/useKeyWithClickEvents: role+keyboard events for overlays
- Fix noArrayIndexKey: use error string as key
- Fix CSS parse: enable tailwindDirectives parser
- Normalize formatting across 80 files with biome check --write

apps/frontend/src/components/ui/popover.tsx

@@ -1,20 +1,20 @@
-"use client"
+"use client";
 
-import * as React from "react"
-import * as PopoverPrimitive from "@radix-ui/react-popover"
+import * as PopoverPrimitive from "@radix-ui/react-popover";
+import type * as React from "react";
 
-import { cn } from "@/lib/utils"
+import { cn } from "@/lib/utils";
 
 function Popover({
   ...props
 }: React.ComponentProps<typeof PopoverPrimitive.Root>) {
-  return <PopoverPrimitive.Root data-slot="popover" {...props} />
+  return <PopoverPrimitive.Root data-slot="popover" {...props} />;
 }
 
 function PopoverTrigger({
   ...props
 }: React.ComponentProps<typeof PopoverPrimitive.Trigger>) {
-  return <PopoverPrimitive.Trigger data-slot="popover-trigger" {...props} />
+  return <PopoverPrimitive.Trigger data-slot="popover-trigger" {...props} />;
 }
 
 function PopoverContent({
@@ -37,12 +37,12 @@ function PopoverContent({
           "data-[side=left]:slide-in-from-right-2",
           "data-[side=right]:slide-in-from-left-2",
           "data-[side=top]:slide-in-from-bottom-2",
-          className
+          className,
         )}
         {...props}
       />
     </PopoverPrimitive.Portal>
-  )
+  );
 }
 
-export { Popover, PopoverTrigger, PopoverContent }
+export { Popover, PopoverContent, PopoverTrigger };