#306 docs(releases): account_id override on catalog measurements + valuation

Implements the docs row of recoupable/chat#1974.

• GET /api/catalogs/{catalogId}/measurements gains the optional account_id query param — the ownership check runs against the target account (organization keys acting for member accounts), matching the wording pattern of the 14 ops that already document the override.
• RunValuationRequest (POST /api/valuation) gains the optional account_id body field, with the description spelling out that every side effect (playcount snapshot, catalog claim, roster attach, report email) scopes to the target account.

+12 lines, purely additive; JSON validated. Contract-first — the two api PRs implement the behavior.

🤖 Generated with Claude Code

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Summary by cubic

Adds docs for optional account_id on catalog measurements and valuation so callers can act for an accessible account; previously these endpoints always used the caller’s account.

• GET /api/catalogs/{catalogId}/measurements: optional account_id query param. When provided and accessible, the catalog ownership check runs against that account; omit to use the caller’s account.
• POST /api/valuation: optional account_id body field. All side effects (playcount snapshot, catalog claim, roster attach, report email) scope to that account; omit to run for the caller’s account.

Summary by CodeRabbit

• New Features
  • Added optional account selection for catalog measurement requests.
  • Added optional account selection for valuation runs.
  • Valuation results and related actions can now be scoped to the selected account.
  • Added access to authenticated valuation-run history, with filtering by run type and result count.