fix(governance): make mutations and audit atomic

[XiaoSeS]

What

Closes #615.

Review and promotion mutation entry points now own the application transaction, so domain state, audit persistence, and response-critical projection succeed or roll back together. This completes the transaction-atomicity half left after #782 fixed audit JSON serialization.

Scope

• Add transaction boundaries only to ReviewPortalAppService and PromotionPortalAppService write methods.
• Keep query methods unchanged.
• Reuse AuditLogService default REQUIRED propagation; no outbox or schema change.

Tests

• Review approval rolls back task, version status, latest-version pointer, and search side effects when audit persistence fails.
• Promotion approval rolls back request state and the target skill copy when audit persistence fails.
• Existing success, permission, and history tests remain green.

Signed-off-by: XiaoSeS 87064762+XiaoSeS@users.noreply.github.com