fix(sdks): align pool idle TTL via state store hook

[ninan-nn]

Summary

• Add a generic PoolStateStore.setIdleEntryTtl(poolName, idleTtl) extension hook (default no-op) so SandboxPool stays decoupled from concrete store implementations.
• Update SandboxPool.start() to configure idle TTL through the store interface using config.idleTimeout.
• Refactor InMemoryPoolStateStore to keep default 24h TTL internally and support per-pool TTL via the new hook (without exposing TTL in constructor).
• Add/adjust tests to verify TTL hook behavior and validation.

Testing

• Not run (explain why)
• Unit tests
• Integration tests
• e2e / manual verification

Executed:

• ./gradlew :sandbox:test --tests "com.alibaba.opensandbox.sandbox.infrastructure.pool.InMemoryPoolStateStoreTest" --tests "com.alibaba.opensandbox.sandbox.pool.SandboxPoolTest"

Breaking Changes

• None
• Yes (describe impact and migration path)

Checklist

• Linked Issue or clearly described motivation
• Added/updated docs (if needed)
• Added/updated tests (if needed)
• Security impact considered
• Backward compatibility considered

[Pangjiping]

LGTM