feat(sim): F4.2 the sim protocol, the simulation room and LocalSimHost; M9 measured

packages/protocol holds the one list of /sim messages and checks every
field, naming what is wrong. packages/sim has the simulation room for F and
the web worker: the document's snapshot at start, the engine's clock on the
wall clock with Java's speed as cable delay, subscriptions to cable
activity, a card's new frames and a program's new window lines, capture and
clock kept over a stop, the command line as first action, a core failure
told to every client. LocalSimHost mirrors the document into the worker and
back without echo. M9 in Chromium: 17 examples give the same capture as in
Node, character for character; the room runs in a real worker.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/protocol/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@mdg-filius/protocol",
+  "version": "0.0.0",
+  "private": true,
+  "license": "GPL-3.0-only",
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "dependencies": {
+    "@mdg-filius/core": "0.0.0"
+  }
+}