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/src/app.tsx

@@ -1,8 +1,9 @@
 /**
- * Real-UI assembly closure. Runs only after loader.settled(): the whole
- * layout tree hangs off the built-in 'root' slot (ui-layout registers
- * AppFrame there and renders the child slots internally) — the shell's
- * render is the one ctx-level renderSlot call in the program.
+ * Real-UI assembly closure, invoked by the app-shell plugin once its inject
+ * set is active: the whole layout tree hangs off the built-in 'root' slot
+ * (ui-layout registers AppFrame there and renders the child slots
+ * internally) — the shell's render is the one ctx-level renderSlot call in
+ * the program.
  */
 import type { ReactNode } from 'react'
 import type { Context } from 'cordis'
@@ -12,16 +13,14 @@ import { DocumentTitle } from './DocumentTitle.tsx'
 // Type-only: pulls the runtime's SlotMap declaration merge (the 'root' key) into this program.
 import type {} from '@deepseek-ai/dsh-client-runtime/client'
 
-/** Assembly inputs: the settled root ctx plus the loader's module-table read surface. */
+/** Assembly inputs: the active app-shell plugin ctx (slots/sessions/layout services provided). */
 export interface AssemblyDeps {
-  /** Client root context (all plugin services provided). */
+  /** Client context with the assembly's inject set active. */
   ctx: Context
-  /** Module-table resolver (the loader's require; missing spec = throw). Kept in the seam for future shell needs. */
-  requireModule: (spec: string) => unknown
 }
 
 /**
- * Build the renderApp factory handed to AppRoot.
+ * Build the renderApp factory the app-shell plugin provides to AppRoot.
  * @param deps - assembly inputs.
  * @returns factory producing the real UI tree (called once per AppRoot render after settled).
  */