feat: implement complete invoicing application with CSV import and PDF export

- Add comprehensive CSV import system with drag-and-drop upload and validation
- Create UniversalTable component with advanced filtering, searching, and batch actions
- Implement invoice management (view, edit, delete) with professional PDF export
- Add client management with full CRUD operations
- Set up authentication with NextAuth.js and email/password login
- Configure database schema with users, clients, invoices, and invoice_items tables
- Build responsive UI with shadcn/ui components and emerald branding
- Add type-safe API layer with tRPC and Zod validation
- Include proper error handling and user feedback with toast notifications
- Set up development environment with Bun, TypeScript, and Tailwind CSS

.env.example

@@ -0,0 +1,23 @@
+# Since the ".env" file is gitignored, you can use the ".env.example" file to
+# build a new ".env" file when you clone the repo. Keep this file up-to-date
+# when you add new variables to `.env`.
+
+# This file will be committed to version control, so make sure not to have any
+# secrets in it. If you are cloning this repo, create a copy of this file named
+# ".env" and populate it with your secrets.
+
+# When adding additional environment variables, the schema in "/src/env.js"
+# should be updated accordingly.
+
+# Next Auth
+# You can generate a new secret on the command line with:
+# npx auth secret
+# https://next-auth.js.org/configuration/options#secret
+AUTH_SECRET=""
+
+# Next Auth Discord Provider
+AUTH_DISCORD_ID=""
+AUTH_DISCORD_SECRET=""
+
+# Drizzle
+DATABASE_URL="file:./db.sqlite"