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/modules/src/index.ts

@@ -0,0 +1,175 @@
+/**
+ * Client module system: the browser peer of Node's internal ESM loader, built
+ * as a lazy CJS table. The vendored cordis Loader consumes this object
+ * through its `internal` seam (the only call site is `EntryTree.import` →
+ * `internal.import`), which keeps entry governance (fiber lifecycle, inject
+ * waiting, update/refresh) entirely on the vendored side while this package
+ * owns code arrival.
+ *
+ * Lazy CJS model (web2 §0): executing a plugin bundle only REGISTERS its
+ * factory (`window.__ModuleLoader__.load({id, factory})`); every module body
+ * side effect — including CSS injection — lives inside the factory closure
+ * and runs at materialization, not at script execution. Materialization
+ * (factory(require) → export surface) happens on first import/require and is
+ * memoized in {@link ClientModuleLoader.loadCache}; a factory that requires
+ * another registered-but-unmaterialized module materializes it recursively,
+ * so load order needs no external sequencing.
+ *
+ * Resolution branch order (import): seed word → shell instance; memoized
+ * record → surface; static registry (shell-own modules, e.g. app-shell) →
+ * module; registered factory → materialize; graph row → fetch + execute +
+ * materialize; anything else → throw (loud — the runtime mirror of the
+ * build-time bundle purity gate). The synchronous `require` handed to
+ * factories walks the same order minus the fetch branch: fetching is async,
+ * so only already-executed bundles can be required — and cross-plugin value
+ * imports are a build error anyway.
+ * @module @deepseek-ai/dsh-client-modules
+ */
+
+import { ClientModuleLoaderImpl } from './loader.ts'
+
+export { ClientModuleLoaderImpl }
+
+declare module 'cordis' {
+  interface Context {
+    /** The client module system the web shell provides at boot (contract C5). */
+    modules: ClientModuleLoader
+  }
+}
+
+/**
+ * One composed client entry pushed by the host (web2 §0 graph row).
+ * `immediately` marks stage-one prefetch; `inject` is informational graph
+ * metadata (the authoritative edges live in each package's dshClient
+ * declaration and reach fibers through entry creation).
+ *
+ * Wire contract, held on both sides: the producing peer lives in
+ * `@deepseek-ai/dsh-host-webserver` (host packages keep zero workspace
+ * dependencies, so neither side imports the other's shape — drift between
+ * the two declarations is a bug against the web2 contract).
+ */
+export interface WebBootEntry {
+  /** Entry name == package name (or a shell-owned pseudo id, e.g. app-shell). */
+  id: string
+  /**
+   * Bundle endpoint, '/plugins/<id>/client.js?rev=<rev>'. Absent only on
+   * shell-owned pseudo rows (app-shell) whose module is statically registered
+   * — a row that is neither fetchable nor static-registered fails loud.
+   */
+  url?: string
+  /** Bundle content hash (cache-busting consistency anchor); absent with url. */
+  rev?: string
+  /** Package-name dependency edges, informational (preflight display / HMR diffing). */
+  inject?: string[]
+  /** Stage-one prefetch mark: fetch + execute (factory registration) during module-face boot. */
+  immediately?: boolean
+}
+
+/** The composed client entry graph the host injects as `window.__DSH_BOOT__` (dual-held wire contract — see {@link WebBootEntry}). */
+export interface WebBootGraph {
+  /** Consistency anchor over the whole graph (content + bundle hashes). */
+  rev: string
+  /** Composed entries; order carries no semantics (activation order is fiber inject waiting). */
+  entries: WebBootEntry[]
+}
+
+/** The shape a client bundle hands to `window.__ModuleLoader__.load` (registration handoff, contract C6). */
+export interface ClientPluginHandoff {
+  /** Plugin id (package name) — the registration key; must match the graph row being executed. */
+  id: string
+  /**
+   * Closure factory holding the whole bundle body: receives the synchronous
+   * require bound to the module table and returns the bundle's export
+   * surface. Runs once, at materialization.
+   */
+  factory: (require: (spec: string) => unknown) => Record<string, unknown>
+}
+
+/** Window surface this loader owns (bundle side of the handoff protocol) plus the host-injected graph. */
+export interface DshWindow {
+  /** Host-composed entry graph, injected before the shell bundle runs. */
+  __DSH_BOOT__?: WebBootGraph
+  /** Bundle registration sink; installed once per page by {@link createClientModuleLoader} (contract C6). */
+  __ModuleLoader__?: { load(handoff: ClientPluginHandoff): void }
+}
+
+/** Per-module bookkeeping in {@link ClientModuleLoader.loadCache} (module-graph seam, flat today). */
+export interface ClientModuleRecord {
+  /** Module id (entry name / package name). */
+  id: string
+  /** The materialized export surface (factory `module.exports`, or the shell module for static registrations). */
+  surface: unknown
+  /** Owned `<style data-plugin>` tag ids (`data-plugin-css` values) injected during materialization. */
+  styles: string[]
+  /** Observed `require()` edges (module-graph seam; only table words can appear today). */
+  edges: Set<string>
+}
+
+/**
+ * The internal-seam subset the vendored Loader and the client HMR plugin
+ * consume. Mounted on `ctx.loader.internal` by the shell boot and provided
+ * as `ctx.modules` (contract C5).
+ */
+export interface ClientModuleLoader {
+  /** Discriminant against Node's internal loader shapes ('v1'/'v2'). */
+  version: 'client'
+  /** Materialized-module registry: id → record. The governance-side read face for entry export surfaces. */
+  loadCache: Map<string, ClientModuleRecord>
+  /**
+   * Internal seam consumed by the vendored Loader's `tree.import`. Resolves
+   * `specifier` through the branch order documented on the module, fetching
+   * and executing a bundle when needed.
+   * @param specifier - module specifier (entry name or table word).
+   * @param parentURL - importer URL (unused — the client module graph is flat).
+   * @param attrs - import attributes (unused; interface parity with Node's seam).
+   * @returns the module's export surface.
+   */
+  import(specifier: string, parentURL: string, attrs: Record<string, unknown>): Promise<unknown>
+  /**
+   * Register a shell-own module (app-shell — code that ships inside the shell
+   * bundle and never arrives as a plugin bundle).
+   * @param id - entry name (shell-owned pseudo id).
+   * @param module - the statically imported module namespace.
+   */
+  registerStatic(id: string, module: unknown): void
+  /**
+   * Stage-one arrival: fetch the entry's bundle and execute it, registering
+   * its factory (no materialization — module side effects wait for import).
+   * No-op for static-registered ids and ids whose factory is already
+   * registered; concurrent calls share one in-flight task. To force a fresh
+   * fetch (HMR), {@link invalidate} first.
+   * @param id - graph entry name.
+   */
+  prefetch(id: string): Promise<void>
+  /**
+   * Full reset of one module: drop its registered factory, its materialized
+   * record, and any consumed bundle text, so the next prefetch/import
+   * refetches and re-executes (the HMR invalidation hook).
+   * @param id - entry name to invalidate.
+   */
+  invalidate(id: string): void
+}
+
+/** Options for {@link createClientModuleLoader} (assembled by the web shell at boot). */
+export interface ClientModuleLoaderOptions {
+  /** Host-composed entry graph. */
+  graph: WebBootGraph
+  /** Module-table seed: platform-singleton specifier → shell instance. */
+  staticModules: Record<string, unknown>
+  /** Bundle fetch seam (parallelizable half). Defaults to same-origin fetch().text(). */
+  fetchBundle?: (url: string) => Promise<string>
+  /**
+   * Bundle execution seam (synchronously performs the load() registration).
+   * Defaults to a <script> element carrying the code.
+   */
+  executeBundle?: (code: string, url: string) => void
+}
+
+/**
+ * Build the client module system.
+ * @param options - entry graph, module-table staticModules, fetch/execute seams.
+ * @returns the loader the shell mounts as `ctx.loader.internal` and provides as `ctx.modules`.
+ */
+export function createClientModuleLoader(options: ClientModuleLoaderOptions): ClientModuleLoader {
+  return new ClientModuleLoaderImpl(options)
+}