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/runtime/tsdown.config.ts

@@ -1,23 +1,3 @@
-import type { UserConfig } from 'tsdown'
 import { clientBundle } from '../tsdown.client.ts'
 
-/**
- * Standard dual-entry shape plus the loader lib half: exports["./loader"]
- * promises lib/loader.js (the web shell statically imports the machinery —
- * a loader cannot load itself), and the shared preset only emits
- * lib/{index,invariant}.js, so the extra config supplies it.
- */
-const configs = clientBundle('@deepseek-ai/dsh-client-runtime', ['lib/types/index.js', 'lib/types/invariant.js'])
-
-const loaderLib: UserConfig = {
-  entry: { loader: 'lib/types/client/loader/index.js' },
-  outDir: 'lib',
-  format: ['esm'],
-  platform: 'neutral',
-  target: 'es2024',
-  fixedExtension: false,
-  dts: false,
-  clean: false,
-}
-
-export default [...configs, loaderLib]
+export default clientBundle('@deepseek-ai/dsh-client-runtime', ['lib/types/index.js', 'lib/types/invariant.js'])