feat: Invoice Template System

[DanielEmmanuel1]

Description

This PR implements the Invoice Template System as specified in Issue #268. It allows users to create, manage, and use templates for recurring billing to speed up their invoicing workflow.

Key Changes

• Database Schema: Added InvoiceTemplate model with fields for client info, amount, currency, and usage tracking. Added relation to Invoice to track the source template.
• API Endpoints:
  • GET /api/routes-d/invoices/templates: List active templates (supports favorites/limit).
  • POST /api/routes-d/invoices/templates: Create new templates.
  • PATCH /api/routes-d/invoices/templates/[id]: Update templates.
  • DELETE /api/routes-d/invoices/templates/[id]: Soft-delete templates.
  • POST /api/routes-d/invoices/from-template: Create an invoice using a template with optional overrides.
• Frontend Components:
  • TemplateSelector.tsx: Allows users to pick a template when creating an invoice.
  • TemplateManager.tsx: Full CRUD interface for managing templates.
  • FavoriteTemplates.tsx: Added to the dashboard for quick access to the 3 most-used templates.

Security

• All operations are scoped to the authenticated user via privyId.
• Soft-delete ensures historical invoices created from templates remain linked but the template is hidden from active selection.

Closes #268

[vercel]

@DanielEmmanuel1 is attempting to deploy a commit to the david's projects Team on Vercel.

A member of the Team first needs to authorize it.