Quotes and purchase orders were silently losing their line items.
Quote items field was a multi-relation to stock_items, but PocketBase
stored only the last id as a plain string no matter how it was sent
(JSON string via FormData, raw array, or repeated FormData entries).
Every quote created through the UI had `items: ""` or `items: "<id>"`.
Recreated the field as JSON so an array of stock_item ids round-trips
(companion fields quantities/unitPrices already line up with it).
PO snapshot_items had the same class of bug from the other direction:
String(obj) coerced the snapshot array to "[object Object]", which
PocketBase stored verbatim, rendering the PO as N rows of
"Unknown / £0.00". The form now sends JSON-stringified arrays, and
the reader only trusts a snapshot whose rows actually carry a name.
Also fixes:
- Quote item lines are hydrated from stock_items; the parallel
quantities/unitPrices arrays are the source of truth, so quotes
written before the schema fix still render and total correctly.
- Quote form rejects stock rows where no item was actually picked
from the dropdown, instead of saving an empty stockItemId.
- PO PDF filename is now the plain order number (PO-20261015-001.pdf).
Adds the quotes.items schema migration plus three dev scripts for
creating a quote, re-applying the field fix and rendering a test PDF.
