docs(0012): add generic business partner search endpoint

[nicoprow]

Summary

Adds the generic business partner search endpoint to CX-0012, introducing a unified search across legal entities, sites, and additional addresses in a single request.

Changes

New §1.5.2.13 — Generic Business Partner (Pool Search Result)

Defines the response model for the search endpoint: a combined view of an address with its owning legal entity and optional site, derived from the CX-0074 Gate Generic Business Partner model with Pool-specific adaptations:

• Excluded Gate-only attributes: externalId, nameParts, roles, isOwnCompanyData, externalSequenceTimestamp, createdAt, updatedAt
• Added Pool-specific attributes: isParticipantData, legal entity identifiers (top-level), address.identifiers
• Sub-entities: Business Partner Legal Entity, Business Partner Site, Business Partner Address, Confidence Criteria

New §2.2.1.7 — Business Partner Controller (REQUIRED)

New required resource:

• POST /business-partners/search

Key behaviour specified:

• Search fields: legalName and bpn (anchor fields, at least one required); streetName, postalCode, city (fuzzy); country (exact)
• Fuzzy matching: character normalization (ü/ue, ß/ss, case, punctuation), wildcards (* = any sequence, + = one alphanumeric character)
• Validation: anchor field required; non-empty filter; no leading whitespace on bpn/legalName; legalName minimum 3 characters
• Result filter: IncludeLegalEntities, IncludeSites, IncludeAdditionalAddresses; LegalAndSiteMainAddress included when either LE or site filter is active
• Response: one result per unique BPNA, ordered by relevance, max 100 per page; all search fields apply to all result types regardless of filter

Change Request

https://github.com/catenax-eV/product-standardization-prod/issues/666