Why: The 2026-10-13 login recovery contract (Dev docs/svc-deploy/
2026-10-13-login-recovery-contract.md, plan item 6.7) requires that
established SSE connections stop receiving private events once a
password write destroys their session.
Evidence: go test ./... green; TestSSESessionInvalidationClosesStream
streams over a real HTTP server, invalidates the session via
AdminResetUserPassword, and asserts the stream terminates with the
session-expired marker within the recheck window (SELF, worktree run).
Impact: Session-authenticated event streams revalidate at a 15s
heartbeat cadence (package var, shortened in tests) and terminate on
invalidation; API-key streams are unchanged (key revocation is separate).
EventSource reconnects are rejected by the auth middleware.
Refs: Dev PR #504; login recovery contract section 6.7.
weichen