M8b — v1.1: list_jobs + subscribe

[nficano]

Goal

v1.1: list_jobs + subscribe.

Scope

• Add session.list_jobs/session.jobs payloads and runtime handler with default_job_authorization_policy
• Add job.subscribe/job.subscribed/job.unsubscribe; subscriber fan-out in SessionContext.send using subscriber-scoped event_seq per architecture §2
• Examples: list_jobs/, subscribe/
• Property test for subscriber seq invariant (R4 mitigation)

Spec §

§6.2, §6.6, §7.6

Risk

H (subscriber seq fan-out)