cross-domain slice 1: events as a fed-sx peer + allocate-a-post-to-a-calendar (LIVE)

The first cross-domain federated workflow — behaviors defined by TYPES, across domains.

- events.rose-ash.com is now a fed-sx PEER: a lib/host instance with SX_DOMAIN=events whose 'calendar'
  TYPE declares an on-allocate behavior. Replaces the Python events service (no strangler). serve.sh
  gates domain types/behaviors on SX_DOMAIN (blog=article publish/digest; events=calendar+allocate).
- DIRECTED cross-domain delivery: an activity with :to <peer-base> is delivered to that peer's inbox
  (∪ followers). The wire gains 'to'. So 'allocate' targets the events peer specifically.
- host/blog--allocate-activity/allocate! + POST /:slug/allocate?calendar=<id>; the events calendar
  type's allocate-link DAG (an execute-fold effect) fires on receipt.
- docker-compose: the sx_events service (own store, shared SX_FED_SECRET, externalnet for a future
  events.rose-ash.com Caddy route).

LIVE PROOF: publish 'Gig Night' on blog.rose-ash.com → POST /gig-night/allocate?calendar=main → the
events peer RECEIVES the directed, signed activity (/activities: 'allocate article gig-night') and
its calendar type's on-allocate behavior FIRES (/flows: 'linked gig-night'). blog 218/218, full
conformance green.

NEXT: events runs lib/events (real calendars/recurrence/ticketing); link event→post; shop
(lib/commerce) sells tickets — same federated, type-declared shape.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker-compose.dev-sx-host.yml

@@ -36,9 +36,12 @@ services:
       OCAMLRUNPARAM: "b"
       # TA-live ACTOR MODEL: A's actor identity + base URL. A is FOLLOWED (B follows it), so A has no
       # SX_FOLLOW; it delivers its activities to its followers. SX_FED_SECRET signs/verifies fed POSTs.
+      SX_DOMAIN: "blog"
       SX_ACTOR: "blog.rose-ash.com"
       SX_SELF_URL: "http://sx_host:8000"
       SX_FED_SECRET: "rose-ash-fed-2026-shared-a3f9"
+      # Cross-domain: where to send "allocate a post to a calendar" activities (the events peer).
+      SX_EVENTS_BASE: "http://sx_events:8000"
     volumes:
       # SX source (hot-reload on container restart)
       - ./spec:/app/spec:ro
@@ -82,13 +85,12 @@ services:
       - default
     restart: unless-stopped
 
-  # A second host instance — a federation PEER (B). Host A federates its emitted activities to B's
-  # /inbox; B's engine fires ITS OWN behaviors on A's state changes ("everything works over fed-sx").
-  # B has its own durable store + no peers (receives without re-federating). Reached on the default
-  # network only (not exposed via Caddy).
-  sx_host_b:
+  # The EVENTS domain — a fed-sx peer running lib/host with SX_DOMAIN=events (a "calendar" type whose
+  # on-allocate behavior links posts federated from blog). Replaces the Python events service. Blog
+  # sends directed "allocate" activities to its /inbox. Own durable store; same shared fed secret.
+  sx_events:
     image: registry.rose-ash.com:5000/sx_docs:latest
-    container_name: sx-dev-sx_host_b-1
+    container_name: sx-dev-sx_events-1
     entrypoint: ["bash", "/app/lib/host/serve.sh"]
     working_dir: /app
     environment:
@@ -98,15 +100,13 @@ services:
       SX_HTTP_HOST: "0.0.0.0"
       SX_PERSIST_DIR: /data/persist
       SX_ADMIN_USER: admin
-      SX_ADMIN_PASSWORD: "sx-host-b-camper-2026"
-      SX_SESSION_SECRET: "ta-host-b-sess-9d2e1f"
+      SX_ADMIN_PASSWORD: "sx-events-camper-2026"
+      SX_SESSION_SECRET: "events-sess-9d2e1f"
       SX_SERVING_JIT: "1"
       OCAMLRUNPARAM: "b"
-      # TA-live ACTOR MODEL: B's identity + base. B FOLLOWS A (SX_FOLLOW = A's base) at boot, so A
-      # delivers its activities to B. Same shared SX_FED_SECRET so signatures verify across A↔B.
-      SX_ACTOR: "sx_host_b"
-      SX_SELF_URL: "http://sx_host_b:8000"
-      SX_FOLLOW: "http://sx_host:8000"
+      SX_DOMAIN: "events"
+      SX_ACTOR: "events.rose-ash.com"
+      SX_SELF_URL: "http://sx_events:8000"
       SX_FED_SECRET: "rose-ash-fed-2026-shared-a3f9"
     volumes:
       - ./spec:/app/spec:ro
@@ -115,10 +115,9 @@ services:
       - ./web:/app/web:ro
       - ./shared/static:/app/shared/static:ro
       - ./hosts/ocaml/_build/default/bin/sx_server.exe:/app/bin/sx_server:ro
-      - /root/sx-host-b-persist:/data/persist
+      - /root/sx-events-persist:/data/persist
     networks:
-      # externalnet too, so a Caddy route (e.g. blog-b.rose-ash.com) can reverse_proxy to B — the
-      # public-domain step is external Caddy + DNS config (not in this repo). default = A↔B fed traffic.
+      # externalnet too, so Caddy can reverse_proxy events.rose-ash.com → here (external DNS/route).
       - externalnet
       - default
     restart: unless-stopped