Reimplement: websocket: send/receive reducer & table ids instead of names

This issue tracks reimplementation of the work from stale PR #1883, which is being closed because it is too out of date to merge directly.

Original PR: https://github.com/clockworklabs/SpacetimeDB/pull/1883
Original author: @Centril
Original branch: `centril/websocket-use-ids`
Base branch: `master`

## Original PR summary

# Description of Changes

Receive and send reducer ids and table ids as opposed to names in the SDK.

TODO:

• Host implementation of the above.
• Rust SDK implement of the above.
• C# SDK implementation of the above, https://github.com/clockworklabs/com.clockworklabs.spacetimedbsdk/pull/178
• TS SDK implementation of the above

Fixes https://github.com/clockworklabs/SpacetimeDBPrivate/issues/1091.

API and ABI breaking changes

Yes.

## Follow-up

- Reimplement this change in a fresh PR against current `master`.
- Carry forward any still-relevant context from the original PR discussion and review.
- Link the new implementation PR back to the original stale PR for historical context.

Start by reading stale PR #1883 and its review context, then inspect the current master branch's TypeScript SDK websocket handling. Implement the still-unfinished TypeScript SDK portion so reducer and table IDs are sent and received instead of names, and verify that the API and ABI changes match the already-described host, Rust SDK, and C# SDK behavior.