V149: Catalogue item-supplier sourcing info + CRM cross-refs.

Two additive changes that let the phoenix_kit_catalogue plugin carry per-supplier sourcing detail per item and, later, federate those suppliers against CRM — without changing anything warehouse depends on.

The item's scalar primary_supplier_uuid is not created here — it ships upstream in V146 (a hard FK to phoenix_kit_cat_suppliers). This junction is the richer, per-supplier pricing layer alongside it.

phoenix_kit_cat_item_supplier_info

New junction table: one item can be sourced from several suppliers, each with its own SKU, unit cost/currency, lead time, and MOQ. supplier_uuid is a soft ref (no FK) — it resolves to a CRM party or a local cat_supplier; this is where CRM federation actually lands. There is no "primary" among these rows — the item's default supplier is the V146 primary_supplier_uuid scalar (a hard FK to cat_suppliers); this table is purely the per-supplier pricing layer alongside it.

phoenix_kit_cat_suppliers.crm_company_uuid

Nullable UUID soft cross-module xref from a local supplier record to a CRM company, letting a supplier be gradually federated into CRM without losing its catalogue-local identity.

All operations are idempotent.