feat(01-01): initialize Next.js 16 project with TypeScript and Tailwind

- Next.js 16.1.6 with App Router and src/ directory
- TypeScript configuration with path aliases (@/*)
- Tailwind CSS v4 with PostCSS setup
- ESLint with Next.js config
- Supabase packages: @supabase/supabase-js, @supabase/ssr
- Form packages: zod, react-hook-form
- Simple Leopost placeholder page

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,39 @@
+# Dependencies
+node_modules/
+__pycache__/
+*.pyc
+venv/
+.venv/
+
+# Environment
+.env
+.env.local
+.env.*.local
+
+# Build
+.next/
+dist/
+build/
+out/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+npm-debug.log*
+
+# Data (local dev)
+data/
+*.db
+*.sqlite
+
+# GSD Planning (opzionale - può essere committato)
+# .planning/