refactor(gui): dissolve the tool ring into per-view keyed slots

Four rounds of structural rework on the conversation surface, converging
on one registration model for the whole client:

- Review fixes: open() leaves the inject factory (SessionsService owns
  the semantic); ConversationService mounts via ctx.plugin(); the
  bespoke view registry retires into the 'conversation.view' list slot.
- Ring alignment: createChatView factory retired (components get
  everything through checkable shares at the register call site); the
  hand-rolled t/i18n threading is deleted wholesale — a future
  framework-level i18n will supply t as a standard prop keyed by slot
  name, so no interim manual channel.
- Toolview dissolution: ToolViewRegistry / ToolViewResolver /
  ToolViewOutlet / ctx.toolviews retire. Tool rows are entries of the
  'conversation.chat.toolview' keyed slot (scope: session) declared by
  the chat entry; ToolRowOwnerProps is the unified owner payload;
  GenericToolCard becomes the call-site fallback; registrants are plain
  plugins (inject ['slots','conversation'] as the load-order seam);
  session-dimension dispatch moves into components (useSessions reads
  parentId); trajectory/waterfall gain same-shape slots the day they
  render tool rows (RendersCheck rejects empty declarations). Slot
  names mirror the composition path (<domain>.<entry>.<hole>).
- Staging follows current: cell()/binding() are pure resolution
  (render-safe); the constructor subscribes to the list store and
  followCurrent opens the event window when the current session
  changes — staging IS the open signal, business verbs are the timing,
  React render/commit is decoupled from window lifecycle. A masked
  current (projection gap) keeps the stage untouched so deferred
  teardown semantics survive reconnects.

Agent Note: .agents/notes/implemented/architecture/
2026-07-23-toolview-dissolution.md (bilingual pair) records the
decision, the four rejected alternatives, and the accepted semantic
changes; the web client architecture note and packages/client/AGENTS.md
carry the current-state narrative.

Verified: typecheck 0, duplication 0 clones (478 files), full coverage
run 6190 passed with zero threshold errors, knip 0, doc-sync 24/24,
client aggregate tsc 0, render-count checks (one commit per chunk, zero
row re-renders under streaming) green.

packages/client/ui-conversation/tests/chat-branch-tails.spec.tsx

@@ -1,41 +1,20 @@
 // @vitest-environment jsdom
 // Remaining chat branch tails: MessageItem context/unknown/steering arms,
-// ToolViewOutlet inject cache + crash fallback + retry, StatsLine no-cache
-// join, PendingCard reason strip, AssistantMarkdown single-line reasoning,
-// ChatView view-body fallbacks, and apply's action lambdas.
+// StatsLine no-cache join, PendingCard reason strip, AssistantMarkdown
+// single-line reasoning. (Tool-row dispatch tails live with the keyed-slot
+// machinery specs since the tool ring dissolved into renderSlot.)
 
-import { afterEach, describe, expect, it, vi } from 'vitest'
+import { afterEach, describe, expect, it } from 'vitest'
 import { cleanup, render } from '@testing-library/react'
-import { act } from '@testing-library/react'
-import type { SessionId, ToolResultNode } from '@deepseek-ai/dsh-client-runtime/client'
 import type { RpcId } from '@deepseek-ai/dsh-client-connection/client'
-import { hookOf } from './hook.ts'
-import type { UseSession } from '@deepseek-ai/dsh-client-ui-slots'
-import { ToolViewRegistry } from '@deepseek-ai/dsh-client-ui-conversation/client'
-import type { ToolViewProps, Translate } from '@deepseek-ai/dsh-client-ui-conversation/client'
+import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
 import { MessageItem } from '../src/client/chat/MessageItem.tsx'
 import { PendingCard } from '../src/client/chat/PendingCard.tsx'
 import { AssistantMarkdown } from '../src/client/chat/AssistantMarkdown.tsx'
-import { StatsLine } from '../src/client/chat/StatsLine.tsx'
-import { ToolViewOutlet } from '../src/client/chat/ToolViewOutlet.tsx'
+import { StatsLine, type StatsLineProps } from '../src/client/chat/StatsLine.tsx'
 
 afterEach(cleanup)
 
-const SID = 's1' as SessionId
-
-const result = (callId: string): ToolResultNode => ({
-  kind: 'tool-result', seq: 3, callId,
-  call: { name: 'bash', argsRaw: '{"command":"x"}' },
-  content: [], isError: false, callView: null, resultView: null,
-})
-
-const viewProps = (): ToolViewProps => ({
-  callId: 'c1', toolName: 'bash', block: result('c1'),
-  useSession: (() => { throw new Error('unused') }) as unknown as UseSession,
-  actions: { openDetails: vi.fn() },
-  t: ((k: string) => k) as Translate,
-})
-
 describe('MessageItem arms', () => {
   it('steering bubbles carry the interjection badge and non-text rest blocks', () => {
     const view = render(
@@ -85,71 +64,8 @@ describe('small branch tails', () => {
     }
     const source = { getSnapshot: () => snap, subscribe: () => () => {} }
     const view = render(
-      <StatsLine sessionId={SID} useSession={hookOf(source) as unknown as UseSession} />,
+      <StatsLine useSession={bindSnapshotSelector(source) as unknown as StatsLineProps['useSession']} />,
     )
     expect(view.getByText('10 tokens · 1 turns · 1 steps')).toBeTruthy()
   })
 })
-
-describe('ToolViewOutlet dispatch', () => {
-  it('caches the inject factory per (registration x session) and merges its props', () => {
-    const registry = new ToolViewRegistry()
-    const inject = vi.fn((sessionId: SessionId) => ({ extra: `injected:${sessionId}` }))
-    registry.register('bash',
-      (p: ToolViewProps & { extra: string }) => <div data-testid="row">{p.extra}</div>,
-      { inject })
-    // Pure props machinery: the outlet feeds its own sessionId to the
-    // factory — no provider/context needed (terminal channel form).
-    const view = render(
-      <ToolViewOutlet registry={registry} sessionId={SID} toolName="bash" viewProps={viewProps()} />,
-    )
-    expect(view.getByTestId('row').textContent).toBe(`injected:${SID}`)
-    expect(inject).toHaveBeenCalledTimes(1)
-    // Remount under the SAME session: cache hit, factory not re-run.
-    view.unmount()
-    const second = render(
-      <ToolViewOutlet registry={registry} sessionId={SID} toolName="bash" viewProps={viewProps()} />,
-    )
-    expect(second.getByTestId('row').textContent).toBe(`injected:${SID}`)
-    expect(inject).toHaveBeenCalledTimes(1)
-    // A different session is a distinct cache key: factory runs once more.
-    second.unmount()
-    const other = render(
-      <ToolViewOutlet registry={registry} sessionId={'s2' as SessionId} toolName="bash" viewProps={viewProps()} />,
-    )
-    expect(other.getByTestId('row').textContent).toBe('injected:s2')
-    expect(inject).toHaveBeenCalledTimes(2)
-  })
-
-  it('a crashing custom row falls back to GenericToolCard and retries on re-registration', () => {
-    const registry = new ToolViewRegistry()
-    const consoleError = vi.spyOn(console, 'error').mockImplementation(() => {})
-    // React dev builds re-dispatch boundary-caught errors as window 'error'
-    // events (invokeGuardedCallback); swallow them so vitest sees the caught path.
-    const swallow = (e: Event): void => { e.preventDefault() }
-    window.addEventListener('error', swallow)
-    try {
-      const Bomb = () => { throw new Error('row bomb') }
-      registry.register('bash', Bomb as never)
-      const view = render(
-        <ToolViewOutlet registry={registry} sessionId={SID} toolName="bash" viewProps={viewProps()} />,
-      )
-      // Crash caught: generic row rendered instead.
-      expect(view.getByText('Bash')).toBeTruthy()
-      // A new registration bumps the version; the boundary retries the custom row.
-      act(() => { registry.register('bash', (() => <div data-testid="fixed" />) as never) })
-      expect(view.getByTestId('fixed')).toBeTruthy()
-    } finally {
-      window.removeEventListener('error', swallow)
-      consoleError.mockRestore()
-    }
-  })
-
-  it('registry miss renders the generic row directly', () => {
-    const registry = new ToolViewRegistry()
-    const view = render(
-      <ToolViewOutlet registry={registry} sessionId={SID} toolName="bash" viewProps={viewProps()} />,
-    )
-    expect(view.getByText('Bash')).toBeTruthy()
-  })
-})