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/features/expenses/ExpensesPage.tsx

@@ -1,8 +1,8 @@
 import { useState } from "react";
 import { Route } from "@/routes/_authenticated/expenses";
-import { ExpensesProvider } from "./ExpensesProvider";
 import { ExpensesTabContent } from "./components/ExpensesTabContent";
 import { PeriodicExpensesTabContent } from "./components/PeriodicExpensesTabContent";
+import { ExpensesProvider } from "./ExpensesProvider";
 
 const tabs = [
   { id: "expenses", label: "Gastos" },