Browser multiplayer client: promote the KNI spike to src/LittleSim.Web

LittleSim.Web (Blazor WASM + KNI/WebGL) is a real network client now: it
connects to the dedicated server over WebSocket (ClientWebSocket maps to
the browser socket), applies MrGameEng.Net delta snapshots into its
EntityStore and draws pawns through SpriteBatch — fatigue dims them just
like on desktop. The server address comes from ?server=ws://host:port
in the page URL, defaulting to the page's host on port 9050. The net
contract is mirrored in NetContract.cs (KNI and DesktopGL assemblies
can't mix until the graphics libraries build per platform) with loud
keep-in-sync comments on both sides.

Both clients now smooth replicated positions between 10 Hz snapshots:
NetLerp + NetSmoothingSystem lerp the visual position toward the latest
server position every frame (exponential, ~0.25 s to converge).

Verified against a live LittleSim.Server --listen: the browser client
connects (server log), draws ~3.3k lit pixels of pawns whose layout
changes between samples, and survives 400+ ticks without errors. Found
along the way: requestAnimationFrame freezes in hidden windows — the
game loop only runs while the tab is visible.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -16,8 +16,12 @@ Game design docs live in `docs/` and are written in **Russian**. Engine rules li
 ```
 engine/            mrgameeng git submodule (own repo, own CLAUDE.md)
 src/LittleSim      the game (net8.0); references engine projects directly
-src/LittleSim.Server  dedicated-server prototype: the world headless (engine HeadlessHost),
-                   loads mods/defs without atlases; the future network server grows here
+src/LittleSim.Server  dedicated server: the world headless (engine HeadlessHost) +
+                   WebSocket replication (MrGameEng.Net); also fast-forward and probe modes
+src/LittleSim.Web  browser client (Blazor WASM + KNI/WebGL): connects to the dedicated
+                   server, renders replicated pawns; mirrors the net contract (NetContract.cs)
+                   because KNI and DesktopGL assemblies can't mix — keep in sync with
+                   src/LittleSim/Net/NetSchema.cs. Outside LittleSim.sln's test flow.
 Mods/Core          the game's own content as a mod: About, Defs, Languages, Textures
 Cache/             runtime-built atlases (gitignored)
 docs/              концепт, симуляция, моды, roadmap (Russian)
@@ -34,6 +38,7 @@ dotnet run --project src/LittleSim.Server -- --days 10 --tps 60   # headless fas
 dotnet run --project src/LittleSim.Server -- --listen             # multiplayer world (WebSocket)
 dotnet run --project src/LittleSim -- --connect                    # client → ws://localhost:9050
 dotnet run --project src/LittleSim.Server -- --probe               # CLI check of a running server
+dotnet run --project src/LittleSim.Web                             # browser client (?server=ws://…)
 dotnet test LittleSim.sln                        # runs the engine test suites
 ```