The CreateVendorDialog previously loaded the entire @probo/vendors
JSON bundle client-side and used MiniSearch for fuzzy search. This
replaces it with a GraphQL query against the common_third_parties
database table, searched server-side via ILIKE filtering.
Backend: adds CommonThirdParty GraphQL type, a pkg/thirdparty
service, and a commonThirdParties(name) root query. Frontend:
splits into CommonThirdPartyCombobox (display) and an @inline
fragment read on selection via readInlineData.
Signed-off-by: Émile Ré <emile@getprobo.com>