Add Turso/Vercel deployment configuration

- Updated database connection to support Turso auth token
- Added vercel.json with bun build configuration
- Updated environment schema for production deployment
- Added new features and components for production readiness

drizzle/0000_shiny_post.sql

@@ -0,0 +1,2 @@
+ALTER TABLE `beenvoice_invoice_item` ADD COLUMN `position` integer DEFAULT 0 NOT NULL;
+CREATE INDEX `invoice_item_position_idx` ON `beenvoice_invoice_item` (`position`);