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/ui-conversation/tests/chat-stats-bash-sample.spec.tsx

@@ -8,8 +8,8 @@ import { act, cleanup, fireEvent, render } from '@testing-library/react'
 import type {
   AssistantMessageNode, ConversationSnapshot, SessionId, ToolResultNode,
 } from '@deepseek-ai/dsh-client-runtime/client'
-import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
-import type { UseSession } from '@deepseek-ai/dsh-client-web-react'
+import { hookOf } from './hook.ts'
+import type { UseSession } from '@deepseek-ai/dsh-client-ui-slots'
 import type { ChromeProps, ToolViewProps } from '@deepseek-ai/dsh-client-ui-conversation/client'
 import { ToolViewRegistry } from '@deepseek-ai/dsh-client-ui-conversation/client'
 import { StatsLine, deriveStats } from '../src/client/chat/StatsLine.tsx'
@@ -78,7 +78,7 @@ describe('deriveStats', () => {
 
 describe('StatsLine', () => {
   function props(source: { getSnapshot(): ConversationSnapshot; subscribe(fn: () => void): () => void }): ChromeProps {
-    return { sessionId: SID, useSession: bindSnapshotSelector(source) as unknown as UseSession }
+    return { sessionId: SID, useSession: hookOf(source) as unknown as UseSession }
   }
 
   it('renders the joined stats row and hides with zero steps', () => {