rts: clarify connect method

[marksvc]

RealtimeServer.connect is overloaded and used for different things.

This patch changes the overloads to add clarity to how connect is
used, not used, and the implications.

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• I want to modify the connect method in a followup change. This patch makes our connect overloads more plain, and the followup change should be less confusing as a result.
• This patch should not be changing behaviour, but just adding clarity. (Except there is an added Warning.)
• You may notice unpleasant things as you review this. The patch here isn't trying to improve the behaviour, but preserve it.

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Open in Devin Review

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This change is 

[github-actions]

✅ No screenshot differences — all stories are identical.

View the diff page at: https://pr-4060--sf-screenshot-diffs.netlify.app

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.03%. Comparing base (8d20922) to head (64837a3).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/RealtimeServer/common/realtime-server.ts	83.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4060      +/-   ##
==========================================
- Coverage   81.03%   81.03%   -0.01%     
==========================================
  Files         661      661              
  Lines       43107    43108       +1     
  Branches     7062     7036      -26     
==========================================
  Hits        34931    34931              
- Misses       7017     7018       +1     
  Partials     1159     1159              

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[pmachapman]

@pmachapman reviewed 6 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on marksvc).