refactor: move batch suspension methods from EE to CE

[genro]

Problem

Batch suspension methods are currently in TenantsTable_EE but they are useful for CE too:

• Single-tenant (CE) can still have multiple batches (campaigns, newsletters)
• Suspending/activating a batch is operational control, not multi-tenant management
• No dependency on EE features (API keys, multi-tenant auth)

Current Location (Wrong)

src/enterprise/mail_proxy/entities/tenant/table_ee.py:

• suspend_batch(tenant_id, batch_code)
• activate_batch(tenant_id, batch_code)
• get_suspended_batches(tenant_id)

Target Location (Correct)

src/core/mail_proxy/entities/tenant/table.py:

• Move all three methods to CE table

src/core/mail_proxy/entities/tenant/endpoint.py:

• Add endpoint methods to expose via API/CLI

Tasks

• Move suspend_batch, activate_batch, get_suspended_batches from table_ee.py to table.py
• Add suspend, activate, get_suspended methods to TenantEndpoint
• Update imports if needed
• Update tests