perf: remove cloning/stringify of tracks

[puehringer]

Fix gosling-lang#823
Toward #

Change List

• Removes many deep-clones of spec/data (like JSON.parse(JSON.stringify(...)) or structuredClone(...) as they also copy the underlying values when using json data type. This causes gosling to become very slow on zooming/panning.

TODOs

• Clarify why the clones are actually necessary, and what we might break with removing them
  • In PubSub/event listeners: I understand the idea to return a deep-copy to avoid mutations, however that comes with a high cost. I would prefer this to be in the hands of the users of the library.
  • Everywhere else: I didn't see the spec being mutated inline (except for the cases where we changed it already).

Checklist

• Ensure the PR works with all demos on the online editor
• Unit tests added or updated
• Examples added or updated
• Documentation updated (e.g., added API functions)
• Screenshots for visual changes (e.g., new encoding support or UI change on Editor)

[sehilyi]

Cool, this would be a nice feature to have. Some users previously asked about having multiple methods (e.g., maintaining outliers).