feat(web): grow real node halves in connection and hmr

connection binds the web transport: it injects httpServer + apiProxy and
registers toFetchHandler(ctx.apiProxy) under the /api prefix (the node:http
to fetch bridge moves in from the webserver, keeping the res-close disconnect
detection and drain/close backpressure waits). hmr owns dev reload: a
stat-poll watch per graph row driven by clientModuleHost.onGraphChanged,
rebuilt(id) on content change, and the /plugins/events SSE route (GET/HEAD
guarded); frame types are single-sourced in events.ts shared by both halves.

packages/client/hmr/tsconfig.json

@@ -8,7 +8,7 @@
       "DOM",
       "DOM.Iterable"
     ],
-    "types": []
+    "types": ["node"]
   },
   "include": [
     "src"
@@ -23,6 +23,12 @@
     {
       "path": "../modules"
     },
+    {
+      "path": "../../host/webserver"
+    },
+    {
+      "path": "../../../vendor/schemastery"
+    },
     {
       "path": "../../support/invariants"
     }