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/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-client-web-react
 
-ctx↔React machinery for the slot terminal design: createSlotRenderer (the SlotRenderer implementation the shell installs into the runtime SlotsService), SessionProvider (framework-wired render prop over the host's current-session source), defineStore (the declarative store shell over the internal zustand engine), bindSnapshotSelector, useInvoke. The snapshot-store engine (createSnapshotStore) is framework-internal via the `./store` subpath; business plugins declare stores through defineStore only.
+Shell-side React glue for the slot terminal design: createSlotRenderer (the SlotRenderer implementation the shell installs into the runtime SlotsService), SessionProvider (framework-wired render prop, also injected as a standard seat to entries declaring session-scope children), bindSnapshotSelector (the one hook constructor — hosts and engines traffic in bare observable sources; every hook binds here, cached per source), useInvoke. The snapshot-store engine and defineStore live in runtime (store relocation); business plugins depend on ui-slots types only, never on this package.
 
 ## Model Experience