SSE stream of send-ready missions for the authenticated tenant (§3.3, #23).

The v4 replacement for the sidecar's "poll /sync/missions for status='approved' -> execute" loop: a user-side sender (daemon #25 / plugin v2.0 #26) holds this stream open, sends each mission_ready, then acks via /v4/missions/{id}/ack.

Named text/event-stream events: connected once on open; carries the tenant's auto_threshold. mission_ready a mission to send (lean, send-only projection). heartbeat every ~30s; keep-alive + reports pause (backoff) state. shutdown server is stopping, or the token is no longer valid -> close.

THE AUTO-FIRE GATE LIVES HERE (the §3.3 SCOPE NOTE): a mission auto-fires only when its 0-1 fused_score >= users.auto_threshold (default 1.01 = manual). Enforced in _sse_poll (promotes pending -> approved). DELIVERY IS AT-LEAST-ONCE: a reconnect re-emits any approved-but-unacked mission, so the sender MUST dedupe per mission id (an ack flips status -> 'sent', which drops it from the stream). Exactly-once (an emit-time 'dispatched' status + a timeout re-drive) is a deliberate follow-up, out of scope for the single-sender-per-tenant MVP.