Merge remote-tracking branch 'origin/master' into worktree/web-session-model-selector

# Conflicts:
#	.agents/notes/implemented/architecture/2026-07-15-llm-model-catalog-and-acp-selection.i18n.yaml
#	.agents/notes/implemented/architecture/2026-07-23-client-plugin-loading-model.i18n.yaml
#	apps/cli/src/web.ts
#	apps/web/tests/session-title.snapshot.ts
#	apps/web/tests/smoke-fixture.e2e.ts
#	packages/client/connection/src/client/api.ts
#	packages/client/connection/src/client/fixture.ts
#	packages/client/connection/src/client/index.ts
#	packages/client/runtime/src/client/index.ts
#	packages/client/runtime/src/client/sessions/conversation.ts
#	packages/client/runtime/src/client/sessions/session.ts
#	packages/client/runtime/tests/fake-api.ts
#	packages/client/ui-conversation/src/client/contract/slots.ts
#	packages/client/ui-conversation/src/client/index.ts
#	packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx
#	packages/client/ui-conversation/src/client/skeleton/InputBar.module.css
#	packages/client/ui-conversation/src/client/skeleton/InputBar.tsx
#	packages/client/ui-conversation/tests/chat-stats-bash-sample.spec.tsx
#	packages/client/ui-conversation/tests/chat-toolview-slot.spec.tsx
#	packages/client/ui-conversation/tests/chat-view.spec.tsx
#	packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx
#	packages/client/ui-conversation/tests/skeleton-branches.spec.tsx
#	packages/client/ui-conversation/tests/skeleton.spec.tsx
#	packages/host/apiproxy/README.md
#	packages/host/apiproxy/src/api-proxy.ts
#	packages/host/apiproxy/src/api/rpc.schema.ts
#	packages/host/apiproxy/src/api/rpc.ts
#	packages/host/apiproxy/tests/api-proxy-models.spec.ts
#	packages/host/apiproxy/tests/rpc-schemas.spec.ts
#	packages/host/runtime/README.md
#	packages/llm/llm-deepseek/README.md
#	scripts/translation-pairing.manifest.json
#	tsconfig.client.json

packages/client/ui-model-selector/README.md

@@ -2,7 +2,7 @@
 
 Session-scoped Web model selector. Its browser half occupies `conversation.composer.control`, shows the current catalog name beside the send button, and opens an upward provider-grouped menu. Provider names appear once as group headings; model rows and the trigger show catalog names without repeating the provider route, with the model id as the fallback for an unlisted current target.
 
-The selector primes the advisory directory when it mounts so the trigger can resolve the catalog name, then refreshes it whenever the menu opens. The Session object layer owns loading, selection, partial-provider-failure, and stale-response state. A selection updates only that live session and takes effect at the next prompt-assembly boundary, including while the current step is running. The latest consumed target remains durable through the existing `request/header`; an unused choice is process-local.
+The selector primes the advisory directory when an existing Host session mounts so the trigger can resolve the catalog name, then refreshes it whenever the menu opens. A frontend Session Intent has no Host model route yet, so the selector stays absent and issues no directory RPC until publication clears the intent. The Session object layer owns loading, selection, partial-provider-failure, and stale-response state. A selection updates only that live session and takes effect at the next prompt-assembly boundary, including while the current step is running. The latest consumed target remains durable through the existing `request/header`; an unused choice is process-local.
 
 Catalog membership is not request validation. The current target is included as an unlisted row when its registered provider omits it, while a target whose provider is unavailable remains visible on the trigger with a warning in the menu.