Merge branch 'stack/agent-profiles-1-seam' into stack/agent-profiles-3-wire

master extracted this layer's inline cold-resume resolver into
@deepseek-ai/dsh-api-remotes, whose `setup` was a fixed AgentSetup. A resumed
session composes the preset ITS header recorded, so the option becomes a
function of that header; the resolver builds the setup before the published
re-checks so those stay adjacent to `resume`.

Conflicts:
	docs/cordis-catalog/services.md
	docs/module-graph.md
	packages/host/apiproxy/package.json
	packages/host/apiproxy/src/api-proxy.ts
	pnpm-lock.yaml

packages/host/apiproxy/src/api/sessions.ts

@@ -117,6 +117,15 @@ export interface ModelCatalogFailure {
 export interface SessionModels {
   /** Target selected for the session's next assembled step. */
   current: ModelTarget
+  /**
+   * Whether an adapter currently serves `current.provider`, and therefore
+   * whether this session can start a turn at all. Deliberately NOT derivable
+   * from `groups`: catalog membership is advisory, so a route serving a model
+   * it stopped advertising is absent from the groups yet perfectly usable,
+   * while a route whose adapter is gone can serve nothing. A surface that
+   * blocks input must read this rather than the groups.
+   */
+  routable: boolean
   /** Successfully loaded provider groups. */
   groups: ModelProviderGroup[]
   /** Provider-local failures; successful groups remain usable. */