Import Circle Game (used for testsuite)

[jdetter]

Description of Changes

Describe what has been changed, any new features or bug fixes

• I have taken the circle game and imported it
• This is the base PR for this: https://github.com/clockworklabs/com.clockworklabs.spacetimedbsdk/pull/176

API

• [ ] This is an API breaking change to the SDK

If the API is breaking, please state below what will break

Requires SpacetimeDB PRs

List any PRs here that are required for this SDK change to work

None

Testing

Write instructions for a test that you performed for this PR

• [x] dotnet testsuite still passes
• [x] testsuite builds, although there are no tests to run because those are in a separate PR (https://github.com/clockworklabs/com.clockworklabs.spacetimedbsdk/pull/176)

proof this builds:

[cloutiertyler]

This comment also applies to this precursor PR: https://github.com/clockworklabs/com.clockworklabs.spacetimedbsdk/pull/176#issuecomment-2444969797

[cloutiertyler]

I am going to evaluate whether this should be a submodule prior to merging this.

[Centril]

Rebased this atop of staging (trivial conflict to resolve, rc1 instead of 0.12.*)

[jdetter]

closed in favor of using this as a submodule https://github.com/clockworklabs/com.clockworklabs.spacetimedbsdk/pull/186