Fix receiver dispatch for WebSocket sends and worker Request fetches #386

Part of #382 — v1.0.0 alpha readiness.

Confirmed failures

• src/messaging/WebSocket.res:59-L74: sendArrayBuffer, sendBlob, and sendString lack @send. A compiled packed consumer emits send(socket, payload) instead of socket.send(payload) and throws ReferenceError: send is not defined.
• src/workers/Worker.res:44-L45: fetchWithRequest lacks @send. A compiled consumer emits fetch(self, request), treating the scope as the URL. The review reproduction rejected while parsing [object global].

The adjacent DataView WebSocket overload and string Worker fetch overload already use receiver dispatch correctly.

Acceptance criteria

• Correct receiver annotations for all three affected WebSocket overloads and the worker Request overload.
• Check the inherited shared/service-worker scope paths as well as the base binding.
• Add regression checks that verify the receiver, argument order, payload, and optional initializer forwarding.
• Exercise representative text/binary sends against a local WebSocket endpoint and Request-based fetch in a real worker (local or data: fixture; no public-network dependency).
• Existing compile/feature tests remain green.

Fix the common dispatch rule across these sibling overloads rather than patching only the string-send example.

Coordination

Use the regression infrastructure in #383. Source fixes can be developed in parallel, but this issue should close with executed regression coverage, not only a successful compile.