Replace vendor JSON with common third parties API

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>

pkg/thirdparty/service.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package thirdparty
+
+import (
+	"context"
+	"fmt"
+
+	"go.gearno.de/kit/pg"
+	"go.probo.inc/probo/pkg/coredata"
+)
+
+type Service struct {
+	pg *pg.Client
+}
+
+func NewService(pgClient *pg.Client) *Service {
+	return &Service{pg: pgClient}
+}
+
+func (s *Service) Search(ctx context.Context, name string) ([]*coredata.CommonThirdParty, error) {
+	var parties coredata.CommonThirdParties
+
+	filter := coredata.NewCommonThirdPartyFilter(&name)
+
+	err := s.pg.WithConn(
+		ctx,
+		func(ctx context.Context, conn pg.Querier) error {
+			return parties.LoadAll(ctx, conn, filter)
+		},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("cannot search common third parties: %w", err)
+	}
+
+	return parties, nil
+}