refactor(web): collapse the shell boot into the AppWebEntry class

The four free functions in boot.tsx become one kernel class holding what
must exist before cordis: the parsed BootManifest, the ClientModuleSystem
instance, and the loading-page handles. Context/Loader setup runs in
parallel with the immediately-tier prefetch, but entry creation awaits the
prefetch: materialization is tree.import's synchronous require, so
cross-package require edges (i18n -> runtime/client) need every
immediately-tier factory registered first — unbarriered creation raced
10-25% of boots. The kernel adopts the modules entry (writes the
__DSH_MODULES__ slot pre-cordis, creates the entry first, skips its graph
row), and provide('modules') now lives in the adoption apply. apps/web
drops its host-package edges (composition is apps/cli's job).

packages/client/web/src/index.ts

@@ -1,13 +1,13 @@
 /**
- * Web shell library entry. The shell's product is {@link bootWebShell} —
- * apps/web's vite entry calls it against #root; everything else (AppRoot
+ * Web shell library entry. The shell's product is {@link AppWebEntry} —
+ * apps/web's vite entry runs it against #root; everything else (AppRoot
  * gate, app-shell assembly entry, module-table staticModules, platform constants) is
  * internal to the boot chain. PLATFORM_MODULES is re-exported as the C1
  * single source of truth for the tsdown client externals projection.
  * @module @deepseek-ai/dsh-client-web
  */
 
-export { bootWebShell, type BootSeams } from './boot.tsx'
+export { AppWebEntry, type BootSeams } from './boot.tsx'
 export { AppRoot, type AppRootProps } from './AppRoot.tsx'
 export { buildRenderApp, type AssemblyDeps } from './app.tsx'
 export { DocumentTitle, type DocumentTitleProps } from './DocumentTitle.tsx'