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/src/AppRoot.tsx

@@ -7,7 +7,7 @@
  */
 import { useSyncExternalStore } from 'react'
 import type { ReactNode } from 'react'
-import type { ObservableSnapshot, SnapshotStore } from '@deepseek-ai/dsh-client-web-react'
+import type { ObservableSnapshot, SnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
 import type { LoaderStatus } from '@deepseek-ai/dsh-client-runtime/client'
 import css from './AppRoot.module.css'
 

packages/client/web/src/boot.tsx

@@ -10,7 +10,7 @@
 import { Context } from 'cordis'
 import { createRoot } from 'react-dom/client'
 import type { ReactNode } from 'react'
-import type { ObservableSnapshot } from '@deepseek-ai/dsh-client-web-react'
+import type { ObservableSnapshot } from '@deepseek-ai/dsh-client-runtime/client'
 import { createSlotRenderer } from '@deepseek-ai/dsh-client-web-react'
 import { createClientLoader, type ClientLoaderOptions } from '@deepseek-ai/dsh-client-runtime/loader'
 import { AppRoot } from './AppRoot.tsx'

packages/client/web/src/seed.ts

@@ -13,7 +13,6 @@ import * as ReactDomClient from 'react-dom/client'
 import * as Cordis from 'cordis'
 import * as UiSlots from '@deepseek-ai/dsh-client-ui-slots'
 import * as WebReact from '@deepseek-ai/dsh-client-web-react'
-import * as WebReactStore from '@deepseek-ai/dsh-client-web-react/store'
 import * as UiPrimitives from '@deepseek-ai/dsh-client-ui-primitives'
 
 /**
@@ -29,7 +28,6 @@ export function seedModules(): Record<string, unknown> {
     'cordis': Cordis,
     '@deepseek-ai/dsh-client-ui-slots': UiSlots,
     '@deepseek-ai/dsh-client-web-react': WebReact,
-    '@deepseek-ai/dsh-client-web-react/store': WebReactStore,
     '@deepseek-ai/dsh-client-ui-primitives': UiPrimitives,
   }
 }