refactor(gui): rebuild the client loading kernel as dsh-client-modules with a two-phase boot

The module system moves out of dsh-client-runtime (./loader retired) into
its own package: a lazy CJS table where executing a bundle only registers
its factory and materialization happens at first require, memoized, with
recursive requires self-ordering. ClientModuleSystem is a class; index.ts
keeps the types and a thin factory. Boot is two-phase: phase one prefetches
the immediately tier in parallel (registration only, failures deferred to
phase two's loud import); phase two mounts the vendored Loader with the
module system as internal, creates one entry per graph row plus the
app-shell pseudo-row the kernel appends itself, and settles on an
all-ACTIVE sweep. The shell kernel is self-sufficient: hand-rolled
loader-status stores, no plugin value imports, platform seed list single-
sourced in platform.ts.

packages/client/web/tests/app-root.spec.tsx

@@ -1,42 +1,33 @@
 // @vitest-environment jsdom
 /**
  * AppRoot boot-gate smoke: loading page until the settled signal flips (status
- * alone never opens the gate), fail-loud plugin list, one-pass switch to the
- * real UI. The full browser chain (real loader + bundles) is the e2e's job;
- * this pins the shell-owned gate semantics.
+ * alone never opens the gate), fail-loud entry list + boot failure report,
+ * one-pass switch to the real UI. The full browser chain (real module system
+ * + vendored Loader + bundles) is the e2e's job; this pins the shell-owned
+ * gate semantics. Stores are the kernel-own signals production boot uses
+ * (shell self-sufficiency: the loading page depends on no plugin package).
  */
 import { afterEach, describe, expect, it } from 'vitest'
 import { act, cleanup, render } from '@testing-library/react'
 
 afterEach(cleanup)
-// The snapshot-store engine lives with runtime now; the status-store stub
-// uses the same channel production code does.
-import { createSnapshotStore, type ObservableSnapshot } from '@deepseek-ai/dsh-client-runtime/client'
-import type { LoaderStatus } from '@deepseek-ai/dsh-client-runtime/client'
 import { AppRoot } from '@deepseek-ai/dsh-client-web/src/AppRoot.tsx'
-
-function signal(): ObservableSnapshot<boolean> & { flip: () => void } {
-  let value = false
-  const listeners = new Set<() => void>()
-  return {
-    getSnapshot: () => value,
-    subscribe: (fn) => { listeners.add(fn); return () => { listeners.delete(fn) } },
-    flip: () => { value = true; for (const fn of [...listeners]) fn() },
-  }
-}
+import { createLoaderStatusStore, createSignal } from '@deepseek-ai/dsh-client-web/src/loader-status.ts'
 
 function mount() {
-  const settled = signal()
-  const status = createSnapshotStore<LoaderStatus>({})
+  const settled = createSignal(false)
+  const error = createSignal<string | undefined>(undefined)
+  const status = createLoaderStatusStore()
   let renders = 0
   const utils = render(
     <AppRoot
       settled={settled}
       status={status}
+      error={error}
       renderApp={() => { renders += 1; return <div data-testid="real-ui" /> }}
     />,
   )
-  return { settled, status, counts: () => renders, ...utils }
+  return { settled, status, error, counts: () => renders, ...utils }
 }
 
 describe('AppRoot', () => {
@@ -50,24 +41,34 @@ describe('AppRoot', () => {
   it('all-active status alone does not open the gate (settled signal is the only key)', () => {
     const { status, queryByTestId } = mount()
     act(() => {
-      status.update((d) => { d['a'] = 'active'; d['b'] = 'active' })
+      status.set('a', 'active')
+      status.set('b', 'active')
     })
     expect(queryByTestId('real-ui')).toBeNull()
   })
 
-  it('lists failed plugins and stays on the loading page', () => {
+  it('lists failed entries and stays on the loading page', () => {
     const { status, getByText, queryByTestId } = mount()
     act(() => {
-      status.update((d) => { d['@deepseek-ai/dsh-client-ui-theme'] = 'failed'; d['ok'] = 'active' })
+      status.set('@deepseek-ai/dsh-client-ui-layout', 'failed')
+      status.set('ok', 'active')
     })
     expect(getByText('Failed to load plugins')).toBeTruthy()
-    expect(getByText('@deepseek-ai/dsh-client-ui-theme')).toBeTruthy()
+    expect(getByText('@deepseek-ai/dsh-client-ui-layout')).toBeTruthy()
+    expect(queryByTestId('real-ui')).toBeNull()
+  })
+
+  it('renders the boot failure report even when no entry projected failed', () => {
+    const { error, getByText, queryByTestId } = mount()
+    act(() => { error.set('web boot: 1 entry did not activate\nx: pending (waiting for service: y)') })
+    expect(getByText('Failed to load plugins')).toBeTruthy()
+    expect(getByText(/waiting for service/)).toBeTruthy()
     expect(queryByTestId('real-ui')).toBeNull()
   })
 
   it('flipping settled switches to the real UI in one pass', () => {
     const { settled, getByTestId, queryByText, counts } = mount()
-    act(() => { settled.flip() })
+    act(() => { settled.set(true) })
     expect(getByTestId('real-ui')).toBeTruthy()
     expect(queryByText('HARNESS')).toBeNull()
     expect(counts()).toBe(1)