Automatically select official backtest inputs

[hjcud]

What

• remove client-selected official dataset, execution-policy, and internal version fields from BASIC strategy release
• select the latest locked execution policy and a coherent official dataset set for every compiled-plan resolution
• pin, persist, hash, and publish every selected dataset while retaining the legacy representative fields

Why

Official automatic backtest inputs are server-owned. A single client-selected dataset cannot satisfy strategies that require multiple resolutions.

Impact

BASIC releases fail closed when a coherent official input set is unavailable. Custom backtests and competition flows are unchanged.

Checks

• gradlew :modules:backend-application:test :modules:backend-messaging:test :apps:backend-api:test
• PostgreSQL persistence integration tests for immutable release and official request hash