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

tsconfig.base.json

@@ -97,9 +97,9 @@
       "@deepseek-ai/dsh-client-ui-slots": ["./packages/client/ui-slots/src"],
       "@deepseek-ai/dsh-client-ui-primitives": ["./packages/client/ui-primitives/src"],
       "@deepseek-ai/dsh-client-web-react": ["./packages/client/web-react/src"],
-      "@deepseek-ai/dsh-client-web-react/store": ["./packages/client/web-react/src/store"],
       "@deepseek-ai/dsh-client-connection": ["./packages/client/connection/src"],
       "@deepseek-ai/dsh-client-runtime": ["./packages/client/runtime/src"],
+      "@deepseek-ai/dsh-client-runtime/client": ["./packages/client/runtime/src/client"],
       "@deepseek-ai/dsh-client-runtime/loader": ["./packages/client/runtime/src/client/loader"],
       "@deepseek-ai/dsh-client-ui-layout": ["./packages/client/ui-layout/src"],
       "@deepseek-ai/dsh-client-ui-sidebar": ["./packages/client/ui-sidebar/src"],