fix: reject sendMessage when the websocket reply never arrives

[jaredcat]

Summary

• sendMessage waits on a Promise whose resolve is stored in waitingCallback.
• After EXPECT_RESPONSE_AFTER (default 5s), waitForReply deleted that waiter and logged a warning, but never settled the Promise. Callers (hass.call, entity service methods, registry ops) hung forever.
• The same happened for { type: "result", error: ... } replies: onMessageResult logged and returned without calling the waiter.

This showed up in production as a hung climate.set_preset_mode leaving an automation stuck overnight. The warning was in the logs; the Promise was still pending.

Behavior change

• Timed-out messages now reject with InternalError code MISSING_REPLY.
• Error results now reject with InternalError code RESULT_ERROR.
• Successful replies are unchanged.
• Slow integrations can still raise EXPECT_RESPONSE_AFTER (seconds).

Callers that currently fire-and-forget hass.call / sendMessage without .catch() will start seeing unhandled rejections instead of silent hangs. That is the correct default.

Test plan

• yarn vitest run src/testing/websocket.spec.mts — resolve on result, reject on timeout, reject on error result
• Full suite: 280 passed / 5 skipped
• Manual: call a service against a disconnected/hung integration and confirm the Promise rejects after EXPECT_RESPONSE_AFTER instead of blocking

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.15%. Comparing base (66093d0) to head (388cac2).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #254      +/-   ##
==========================================
+ Coverage   81.79%   82.15%   +0.35%     
==========================================
  Files          47       47              
  Lines        1774     1776       +2     
  Branches      197      207      +10     
==========================================
+ Hits         1451     1459       +8     
+ Misses        322      315       -7     
- Partials        1        2       +1     

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[zoe-codez]

LGTM, thanks for the PR!