Fixes race condition where incomplete state of ViewModelLines could be observed by events fired during model access.

[dmitrivMS]

Problem description

During _constructLines(), the modelLineProjections array was emptied (this.modelLineProjections = [])
While reconstructing (40+ lines of code), synchronous callbacks could fire from model operations
These callbacks tried to access modelLineProjections[index] which was empty/incomplete
Result: Cannot read properties of undefined (reading 'getViewLineMinColumn'|'getViewLineContent'|'getViewLineMaxColumn')

Potentially fixes the following issues

#284539
#283293
#283289
#283288
#283286
#283048
#233161
#213371
#213247
#198172
#283298
#283290
#240205
#240206
#232917
#246657
#175521
#161048
#260073

[Copilot]

Pull request overview

This PR fixes a critical race condition in ViewModelLinesFromProjectedModel._constructLines() where the modelLineProjections array was cleared and rebuilt incrementally. During reconstruction, synchronous callbacks from model operations could fire and attempt to access the incomplete array, causing "Cannot read properties of undefined" errors when calling methods like getViewLineMinColumn, getViewLineContent, or getViewLineMaxColumn.

Key Changes

• Build projections in a local newProjections array instead of directly updating this.modelLineProjections
• Atomically replace this.modelLineProjections only after all projections are built, preventing callbacks from observing partially updated state

[bpasero]

@alexdima can you review this while Henning is out? The issues are among the top crashes in error telemetry as far as I can tell.

[dmitrivMS]

Per discussion with @alexdima my change probably does not fix the root cause of these issues. I'll do more investigation to see if I can construct a solid repo for some of the scenarios and discuss with @hediet once he's back in office.

[hediet]

Looks good! However, I'm not sure it fixes these referenced issues, as I didn't see _constructLines in the stack trace.
I also don't know which event could be fired within that method.