fix(invoices): GET and POST responses missing gig_invoice_items line items

[forgou37]

Bug

The gig_invoice_items table was added today (migration 20260530210000_gig_invoice_items.sql) to support itemized invoices.

The GET /api/gigs/[id]/invoice route and the POST create response do not include line items:

GET handler (route.ts:56)

.select(`
  *,
  worker:profiles!worker_id(id, username, full_name, avatar_url),
  poster:profiles!poster_id(id, username, full_name, avatar_url)
  // ❌ missing: items:gig_invoice_items(...)
`)

POST response — returns invoice_id, pay_url, etc. but not the created line items.

Impact

• Client fetching an invoice after creation cannot display line-item breakdown
• Frontend InvoicePaymentActions / InvoiceCharges receive no item data even when items were saved

Fix

1. Add items:gig_invoice_items(id, description, amount_usd, position) to the GET select
2. Include items in the POST 201 response body

PR to follow.