Fix unhandled websocket error

[rkistner]

We previously fixed some unhandled websocket errors in #11. This covers an additional case: If an invalid frame is sent before the first data, we crash with an error like below:

node:events:496
      throw er; // Unhandled 'error' event
      ^

RangeError: Invalid WebSocket frame: RSV2 and RSV3 must be clear
    at Receiver.getInfo (/home/ralf/src/powersync-service/node_modules/.pnpm/ws@8.18.0/node_modules/ws/lib/receiver.js:194:26)
    at Receiver.startLoop (/home/ralf/src/powersync-service/node_modules/.pnpm/ws@8.18.0/node_modules/ws/lib/receiver.js:155:16)
    at Receiver._write (/home/ralf/src/powersync-service/node_modules/.pnpm/ws@8.18.0/node_modules/ws/lib/receiver.js:94:10)
    at writeOrBuffer (node:internal/streams/writable:572:12)
    at _write (node:internal/streams/writable:501:10)
    at Writable.write (node:internal/streams/writable:510:10)
    at Socket.socketOnData (/home/ralf/src/powersync-service/node_modules/.pnpm/ws@8.18.0/node_modules/ws/lib/websocket.js:1355:35)
    at Socket.emit (node:events:518:28)
    at addChunk (node:internal/streams/readable:561:12)
    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)
Emitted 'error' event on Duplex instance at:
    at Duplex.duplexOnError (/home/ralf/src/powersync-service/node_modules/.pnpm/ws@8.18.0/node_modules/ws/lib/stream.js:37:10)
    at Duplex.emit (node:events:518:28)
    at emitErrorNT (node:internal/streams/destroy:170:8)
    at emitErrorCloseNT (node:internal/streams/destroy:129:3)
    at process.processTicksAndRejections (node:internal/process/task_queues:90:21) {
  code: 'WS_ERR_UNEXPECTED_RSV_2_3',
  [Symbol(status-code)]: 1002
}

This adds a temporary error handler right when the websocket is first opened, then deregisters it once the WebsocketDuplexConnection takes over.

Originally reported on Discord.

AI Usage

Used Codex gpt-5.6 to reproduce and fix the issue.

Manually reviewed and tested, in addition to the new automated test that confirms the issue.

[changeset-bot]

🦋 Changeset detected

Latest commit: b857f0c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@powersync/service-rsocket-router	Patch
@powersync/service-core	Patch
@powersync/service-module-core	Patch
@powersync/service-image	Patch
@powersync/service-module-convex	Patch
@powersync/service-module-mongodb-storage	Patch
@powersync/service-module-mongodb	Patch
@powersync/service-module-mssql	Patch
@powersync/service-module-mysql	Patch
@powersync/service-module-postgres-storage	Patch
@powersync/service-module-postgres	Patch
test-client	Patch
@powersync/service-schema	Patch

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