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/runtime/tests/session.spec.ts

@@ -129,6 +129,31 @@ describe('model selection', () => {
     })
   })
 
+  it('restores the logged target when a mount-time directory refresh overlaps history', async () => {
+    const { api, session } = makeSession()
+    const history = deferred<Awaited<ReturnType<FakeApiClient['onHistory']>>>()
+    const directory = deferred<Awaited<ReturnType<FakeApiClient['onModels']>>>()
+    api.onHistory = () => history.promise
+    api.onModels = () => directory.promise
+
+    const opening = session.open()
+    const refreshing = session.refreshModels()
+    directory.resolve(err({ code: 'internal', message: 'catalog unavailable', details: {} }))
+    await refreshing
+    history.resolve(ok({
+      events: [],
+      hasMore: false,
+      modelTarget: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+    }))
+    await opening
+
+    expect(session.getSnapshot().modelSelection).toMatchObject({
+      current: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+      status: 'error',
+      error: { code: 'internal', message: 'catalog unavailable' },
+    })
+  })
+
   it('keeps the previous target and directory when selection fails, then accepts a retry', async () => {
     const { api, session } = makeSession()
     await session.open()
@@ -388,19 +413,33 @@ describe('paging', () => {
 })
 
 describe('prompt and cancel errors', () => {
-  it('sends content through session.prompt with the mode passed through', async () => {
+  it('sends content through session.prompt; composerPhase steps blank → engaging synchronously at send entry', async () => {
     const { api, session } = makeSession()
-    const result = await session.prompt([{ type: 'text', text: '要发的' }], 'queue')
+    // The blank → engaging edge fires before the RPC settles: the first-send
+    // flow reads the phase on the session area's first frame to keep the
+    // guidance hero from flashing back in.
+    expect(session.getSnapshot().composerPhase).toBe('blank')
+    const inFlight = session.prompt([{ type: 'text', text: '要发的' }], 'queue')
+    expect(session.getSnapshot().composerPhase).toBe('engaging')
+    const result = await inFlight
     expect(result.ok).toBe(true)
+    // Monotone: settlement alone does not step the phase anywhere.
+    expect(session.getSnapshot().composerPhase).toBe('engaging')
     expect(api.callsOf('session.prompt')).toMatchObject([{ sessionId: SID, mode: 'queue', content: [{ type: 'text', text: '要发的' }] }])
+    // First content lands (running turn): engaging → active.
+    session.handleRunning(true)
+    expect(session.getSnapshot().composerPhase).toBe('active')
   })
 
-  it('business failure lands in promptError with op=send', async () => {
+  it('business failure lands in promptError with op=send; the phase stays engaging (retry, no hero bounce)', async () => {
     const { api, session } = makeSession()
     api.onPrompt = () => Promise.resolve(err({ code: 'agent-busy', message: 'busy', details: { reason: 'x' } }))
     const result = await session.prompt([{ type: 'text', text: '失败的' }], 'queue')
     expect(result.ok).toBe(false)
     expect(session.getSnapshot().promptError).toMatchObject({ op: 'send', error: { code: 'agent-busy' } })
+    // Failed first prompt: composer + error strip is the retry surface —
+    // blank is unreachable once a send was initiated.
+    expect(session.getSnapshot().composerPhase).toBe('engaging')
   })
 
   it('lands cancel failures in promptError with op=stop', async () => {