docs(adr 070): note the self-limiting from_wss drop monitor (CON-18)

Documents the CON-18 disposition in the v1 session-lifetime section
(teardown handle still future work, but a dead import no longer leaves
a permanent monitor task) and adds the consequence pair: dead imports
self-clean after EOF + bounded grace; registrations landing past the
grace window fall back to the 30s sweeper deadline.

docs/architecture/decisions/070-from-wss-consumer-adapter.md

@@ -116,8 +116,14 @@ layer is done with the import. Consequences, stated explicitly:
   surface as live for the process lifetime. A reconnecting assembly
   layer should tear down its whole registry and re-import, accepting
   the accumulated server-side sessions until the remote times them out.
-- A close/teardown handle (and with it, safe reconnect) is future work;
-  v1 deliberately does not build a reconnect layer (OQ-03).
+- **Close/teardown handle**: future work; there is no
+  `WssSession::close` in v1 (OQ-03). The connection-drop monitor is
+  however self-limiting (review-002 CON-18): once WS read EOF is
+  observed, pending calls fail with retryable `CONNECTION_CLOSED`,
+  registrations racing the drop are drained by a fast-fail sweep
+  (50 ms interval) during a bounded post-EOF grace window (8
+  consecutive empty drains), and the monitor task then ends — a dead
+  import leaves no permanent task behind.
 
 ## Consequences
 
@@ -129,6 +135,10 @@ layer is done with the import. Consequences, stated explicitly:
   construction (server upgrade path + consumer path share it).
 - Same-protocol import means zero translation: the remote node's ops
   appear in the local registry with their real specs and error schemas.
+- A dead import (peer gone) self-cleans: after EOF the drop monitor
+  fails everything pending, drains drop-racing registrations for a
+  bounded grace window, and ends — no per-dead-session task leak
+  scales with import count (review-002 CON-18).
 
 **Negative:**
 
@@ -138,6 +148,11 @@ layer is done with the import. Consequences, stated explicitly:
   keepalive/timeout tuning — deployment concern, but worth documenting.
 - Reconnection semantics are initially minimal (OQ-03); a consumer
   wanting hot re-registration must wait for or build the policy.
+- Registrations landing in the pending map after the bounded post-EOF
+  grace window elapses wait for the 30 s sweeper deadline instead of
+  failing fast — acceptable because registration-vs-EOF races resolve
+  well within the window in practice, and the mux write-failure path
+  covers the rest.
 
 ## References