[P1][Sprint 2][Parity] Match the Excel OILPRICE_GET catalog using a shared contract

[karlwaldman]

Why

Sheets says its endpoint catalog aligns with Excel, but omits rig counts, storage, EIA inventories, OPEC production, bunker fuels, well production, permits, drilling intelligence, and analytics. Both catalogs are hand-maintained.

Acceptance criteria

• Add reviewed Sheets patterns for the missing Excel families.
• Add real-shape fixtures and numeric/null/nested rendering tests.
• Cover entitlement, no-data, malformed success, and credential-query rejection.
• Generate or validate both allowlists against one versioned machine-readable contract.
• Publish a customer-readable endpoint matrix.
• Fail CI when a claimed cross-add-in capability diverges.

Delivery

Sheets release independent of Excel and Rails.