Merge remote-tracking branch 'origin/master' into xjt/generated-docs-zh-translation-apply

# Conflicts:
#	.agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.i18n.yaml
#	.agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.zh.md
#	docs/architecture.i18n.yaml
#	docs/architecture.zh.md
#	docs/user/guide/providers.i18n.yaml
#	docs/user/guide/providers.zh.md
#	docs/user/guide/quickstart.i18n.yaml
#	docs/user/guide/quickstart.zh.md
#	packages/boot/app-boot/README.i18n.yaml
#	packages/boot/app-boot/README.zh.md
#	packages/bundle/headless/README.i18n.yaml
#	packages/bundle/headless/README.zh.md

scripts/gen-cordis-catalog.ts

@@ -44,6 +44,7 @@ export { REGION_BEGIN, REGION_END }
  */
 export const SERVICE_PAGE: Record<string, string> = {
   agentLoop: 'core.md',
+  agentDefaultModel: 'core.md',
   agents: 'core.md',
   approval: 'approval.md',
   bash: 'bash.md',
@@ -196,6 +197,7 @@ export const LINK_MAP: Readonly<Record<string, string>> = {
   AgentCancelCause: 'core.md',
   AgentFactory: 'core.md',
   AgentHandle: 'core.md',
+  ModelSelection: 'core.md',
   AgentOptions: 'core.md',
   AgentStatus: 'core.md',
   ContentBlock: 'llm-streaming.md',

scripts/gen-doc-graphs.ts

@@ -307,6 +307,14 @@ const SERVICE_ROLES: ServiceRole[] = [
     consumers: ['agent-loop', 'acp', 'subagent-inprocess'],
     note: 'Owns live Agent handles, the create/resume factory seam, and process-local initiator propagation.',
   },
+  {
+    key: 'agentDefaultModel',
+    pkg: 'agent-default-model',
+    title: 'Default Agent model selection',
+    mode: 'core',
+    consumers: ['headless', 'host-apiproxy'],
+    note: 'Layers the default ModelSelection through settings so direct and Host-backed Agent front doors share one state owner.',
+  },
   {
     key: 'agentLoop',
     pkg: 'agent-loop',

scripts/verify-package-readme-model-experience.ts

@@ -48,6 +48,7 @@ const SENTENCE_MODEL_EXPERIENCE: Readonly<Record<string, SentenceContract>> = {
   'packages/bash/pwsh-local': { kind: 'indirect', reason: 'The executor backend delegates model rendering to dsh-tool-pwsh.' },
   'packages/code-runtime/code-runtime': { kind: 'indirect', reason: 'The service interface delegates model rendering to Code Mode in dsh-tools.' },
   'packages/code-runtime/code-runtime-worker': { kind: 'indirect', reason: 'The worker backend delegates model rendering to Code Mode in dsh-tools.' },
+  'packages/core/agent-default-model': { kind: 'indirect', reason: 'The service supplies a ModelSelection; request assembly and adapters own the model-visible request.' },
   'packages/typert/registry': { kind: 'none', reason: 'Runtime type registry; consumers (cordis_inspect, wire faces, gates) own any model-visible projection of registry contents.' },
   'packages/typert/loader': { kind: 'none', reason: 'Loader integration only registers generated artifacts; consumers own any model-visible projection.' },
   'packages/e2b/e2b': { kind: 'none', reason: 'The shared remote-runtime owner registers no model context; provider adapters and consumers own rendered effects.' },
@@ -68,7 +69,7 @@ const SENTENCE_MODEL_EXPERIENCE: Readonly<Record<string, SentenceContract>> = {
   'packages/client/ui-deliverables': { kind: 'none', reason: 'Browser-side UI plugin layer; registers no model surface.' },
   'packages/client/ui-slash': { kind: 'none', reason: 'Browser-side UI plugin layer; registers no model surface.' },
   'packages/client/ui-command': { kind: 'indirect', reason: 'The dispatch paths trigger the host command.execute RPC; each command handler\'s host package owns any model-visible effect.' },
-  'packages/client/ui-model': { kind: 'indirect', reason: 'Selection routes session.selectModel; the host snapshots the target at the next prompt-assembly boundary and owns the model-visible effect.' },
+  'packages/client/ui-model': { kind: 'indirect', reason: 'Selection routes session.selectModel; the Host snapshots the selection at the next prompt-assembly boundary and owns the model-visible effect.' },
   'packages/client/ui-goal': { kind: 'indirect', reason: 'The strip verbs route goal.* mutations; the host GoalService owns the model-visible goal/change context message.' },
   'packages/client/ui-permission': { kind: 'indirect', reason: 'The picker submits the host /permission command; the knob events it appends own the model-visible effect through the sandbox/approval consumers.' },
   'packages/client/ui-plan': { kind: 'indirect', reason: 'The chip dispatches /plan off; dsh-plan-mode owns the model-visible policy, exit tool, and logged state.' },
@@ -94,7 +95,7 @@ const SENTENCE_MODEL_EXPERIENCE: Readonly<Record<string, SentenceContract>> = {
   'packages/host/webserver': { kind: 'none', reason: 'The HTTP carrier bridges browser and API handler and registers no model surface.' },
   'packages/host/frontend-static': { kind: 'none', reason: 'The SPA dist server answers browser asset requests and registers no model surface.' },
   'packages/bundle/base': { kind: 'indirect', reason: 'The bundle is a patch-list carrier; each inserted row\'s package owns its model surface.' },
-  'packages/bundle/headless': { kind: 'none', reason: 'The one-shot runner submits the task as an ordinary user message; prompts and tools belong to the composed base/web bundles.' },
+  'packages/bundle/headless': { kind: 'none', reason: 'The one-shot runner submits the task as an ordinary user message; prompts and tools belong to the composed base and headless bundles.' },
   'packages/llm/llm': { kind: 'none', reason: 'The adapter registry forwards already-assembled requests unchanged.' },
   'packages/llm/token-meter': { kind: 'indirect', reason: 'The measurement service leaves model-visible changes to its consumers.' },
   'packages/lsp/lsp': { kind: 'indirect', reason: 'The provider registry delegates model rendering to dsh-tool-lsp.' },