host P1: types DECLARE behavior, runner DERIVED (LIVE-VERIFIED)

Generalizes the hardcoded publish trigger into declared, capability-routed behavior.

- Types carry :behavior — flat string-keyed bindings {"verb" "type" "dag"} on the type-post
  (persist-safe, like :type-relations). The "article" type declares on-create → the "publish" DAG.
- host/blog--load-behaviors! gathers ALL posts' declarations into a registry at boot (serve.sh); the
  trigger match (host/blog--triggers :match = host/blog--match-behaviors) consults it. Hardcoded
  create+article trigger removed.
- Runner DERIVED (DEBT #2 fixed): match resolves :dag via host/blog--dag-registry and picks the
  runner via host/flow--select-runner over host/blog--runner-fleet ([exec-runner]; RA joins at
  RA-live). Each binding carries its :runner; behavior/-run-binding now uses the binding's runner
  (else the engine default) — so the capability model drives the LIVE engine.
- The type-def view shows each behavior + its derived runner (host/blog--behavior-lines).

LIVE PROOF: /article shows 'on create → publish DAG · needs {effect, branch} · runner: synchronous
(exec-fold)'; publishing on blog.rose-ash.com fired /flows validate+notify via the DECLARED path.
blog 213/213 (+3 P1), full host conformance 610/610. FINDING: load-behaviors! scans all posts, not
is-type?-filtered (article failed is-type? on the durable store though it passed in-memory).

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

lib/host/serve.sh

@@ -185,6 +185,11 @@ EPOCH=1
   echo "(epoch $EPOCH)"
   echo "(eval \"(host/blog-seed-types!)\")"
   EPOCH=$((EPOCH+1))
+  # P1: gather the types' declared :behavior bindings into the registry the trigger match
+  # consults (so publishing an article fires its declared on-publish DAG, runner derived).
+  echo "(epoch $EPOCH)"
+  echo "(eval \"(host/blog--load-behaviors!)\")"
+  EPOCH=$((EPOCH+1))
   # Seed a live demo of the composition fold (plans/composition-objects.md): /compose-demo
   # is one composition object rendered by host/comp-render — renders differently by context.
   echo "(epoch $EPOCH)"