902 canvas tracer controllerjs unit tests again PR

[sbarber2]

@simsong requesting review before merge because Claude transformed canvas_tracer_controller from a .js to a .mjs so thought it worth a second look.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.43%. Comparing base (a279cc9) to head (c5eeaac).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #905      +/-   ##
==========================================
+ Coverage   70.53%   72.43%   +1.89%     
==========================================
  Files          48       49       +1     
  Lines        5192     5673     +481     
  Branches      273      375     +102     
==========================================
+ Hits         3662     4109     +447     
- Misses       1398     1432      +34     
  Partials      132      132              

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[sbarber2]

I think all this looks good. I'm holding off merging so we can coordinate the changes to canvas_tracer_controller.[m]js between this PR and PR #903

[simsong]

we were having so many problems with the fake jquery, I switched back to real jquery. It caused a bunch of changes.