refactor(gui): move the snapshot-store engine into the client runtime

The data layer no longer depends on the React glue package, and business
plugins no longer depend on web-react at all:

- The store engine (zustand vanilla + immer + persist + dev freeze),
  defineStore, and shallowEqual move to @deepseek-ai/dsh-client-runtime,
  exported from the ./client main entry — no ./store subpath survives on
  either package (the web-react one is deleted, none is opened on runtime).
- Store products are bare snapshot sources: useSelector leaves
  SnapshotStore/StoreInstance and Session; every hook is composed at the
  binding site in web-react's renderer (per-source cached uSES binding).
  The SlotRendererHost sessions face carries bare observables only.
- SessionProvider becomes a standard-kit seat: an entry whose children
  declare a session-scope slot receives the framework component as a prop,
  retiring the last value import of web-react from plugin packages.
  UseSession and the session-area types now live in ui-slots.
- web-react shrinks to the shell-only React glue (renderer, providers,
  uSES bridge); zustand/immer belong to runtime alone; the module-table
  seed and tsdown externals drop the web-react/store seat.
- NODE_ENV replacement is defined once in the shared tsdown client preset
  (browser bundles inline the engine and lost vite's define); the 3-line
  process.env typecheck shim moves to runtime with the engine.
- Stray tsc artifacts (.js/.d.ts/.d.ts.map beside sources under src/)
  swept repo-wide; they shadow real sources under vitest resolution.

Verified: both aggregate typecheck programs at zero; 604 client tests
green; repo-wide grep for web-react/store at zero; real-host playwright
run 7/7 including persist round-trip.

ci: fix test/docs

packages/client/web-react/src/bind.ts

@@ -1,19 +1,21 @@
 /**
- * uSES bridge: turns any {@link ObservableSnapshot} into a typed selector
- * hook. Client-side-rendered only, so no server snapshot is wired.
+ * uSES bridge: turns any bare observable snapshot source into a typed
+ * selector hook. Client-side-rendered only, so no server snapshot is wired.
+ * This is the ONE hook constructor in the client stack — engines and hosts
+ * traffic in bare sources; binding happens on the React side.
  */
 import { useSyncExternalStoreWithSelector } from 'use-sync-external-store/shim/with-selector.js'
-import type { ObservableSnapshot, SnapshotSelectorHook } from './store/index.ts'
+import type { HostObservable, SnapshotSelectorHook } from '@deepseek-ai/dsh-client-ui-slots'
 
 /**
- * Bind an observable snapshot source to a typed uSES selector hook.
+ * Bind a bare observable source to a typed uSES selector hook.
  * subscribe/getSnapshot are captured once per source into stable closures
  * (also re-binds `this` for method-based sources), so components never
  * resubscribe across renders. Equality defaults to Object.is.
- * @param w - snapshot source (Session object or snapshot store).
+ * @param w - snapshot source (engine store, Session object, store instance).
  * @returns the selector hook.
  */
-export function bindSnapshotSelector<T>(w: ObservableSnapshot<T>): SnapshotSelectorHook<T> {
+export function bindSnapshotSelector<T>(w: HostObservable<T>): SnapshotSelectorHook<T> {
   const subscribe = (fn: () => void) => w.subscribe(fn)
   const getSnapshot = () => w.getSnapshot()
   return function useSelector<S>(sel: (s: T) => S, eq?: (a: S, b: S) => boolean): S {