chore: initial commit (Ausgangszustand der Vorlage)

.claude/rules/frontend.md

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+---
+paths:
+  - "src/components/**"
+  - "src/app/**/page.tsx"
+  - "src/app/**/layout.tsx"
+  - "src/hooks/**"
+---
+
+# Frontend Development Rules
+
+## shadcn/ui First (MANDATORY)
+- Before creating ANY UI component, check if shadcn/ui has it: `ls src/components/ui/`
+- NEVER create custom implementations of: Button, Input, Select, Checkbox, Switch, Dialog, Modal, Alert, Toast, Table, Tabs, Card, Badge, Dropdown, Popover, Tooltip, Navigation, Sidebar, Breadcrumb
+- If a shadcn component is missing, install it: `npx shadcn@latest add <name> --yes`
+- Custom components are ONLY for business-specific compositions that internally use shadcn primitives
+
+## Import Pattern
+```tsx
+import { Button } from "@/components/ui/button"
+import { Card, CardHeader, CardTitle, CardContent } from "@/components/ui/card"
+```
+
+## Component Standards
+- Use Tailwind CSS exclusively (no inline styles, no CSS modules)
+- All components must be responsive (mobile 375px, tablet 768px, desktop 1440px)
+- Implement loading states, error states, and empty states
+- Use semantic HTML and ARIA labels for accessibility
+- Keep components small and focused
+- Use TypeScript interfaces for all props
+
+## Auth Best Practices (Supabase)
+- Use `window.location.href` for post-login redirect (not `router.push`)
+- Always verify `data.session` exists before redirecting
+- Always reset loading state in all code paths (success, error, finally)