Free-text company search for the dashboard's global search, backed by OpenSearch. Matches an exact companyId or domain, then the company name (whole words, prefix, and a fuzzy fallback), ranked by relevance and capped at 25 hits. Use GET /companies for paginated browsing and filtering.

Declared before GET /companies/{companyId} on purpose — tsoa registers routes in declaration order, so the reverse would make /companies/search resolve as a company whose id is literally "search".