Serve subscriptions/listen with a pluggable event bus (SEP-2575) (#3035)

examples/stories/manifest.toml

@@ -68,6 +68,12 @@ lowlevel   = false
 transports = ["in-memory", "http-asgi"]
 era        = "dual-in-body"
 
+[story.subscriptions]
+# subscriptions/listen exists only on the 2026 wire, so there is no legacy leg.
+# The listen request parks for the stream's lifetime; the client ends it by
+# cancelling the awaiting scope (the spec's client-side close).
+era = "modern"
+
 [story.schema_validators]
 
 [story.middleware]
@@ -166,7 +172,6 @@ fixed_port    = 8000                            # issuer/PRM metadata bake in :8
 
 [deferred]
 caching       = "client honouring + per-result override unlanded"
-subscriptions = "#2901 — Client.listen / ServerEventBus"
 tasks         = "SEP-2663 — tasks extension runtime (server-decided augmentation, CreateTaskResult)"
 skills        = "#2896 — SEP-2640"
 events        = "#2901 + #2896"