Fix memory leak by making NativeFinalizer instances static

[Copilot]

Fix memory leak by making NativeFinalizer instances static

The issue is that NativeFinalizer instances were being created as instance variables instead of static variables. According to Dart FFI best practices, finalizers should be static and shared across all instances of a class for proper memory management.

Root Cause

Creating a new NativeFinalizer for each instance is inefficient and can prevent proper finalization:

• Performance overhead from creating multiple finalizers
• Dart runtime may not efficiently manage finalization
• Memory accumulates because finalizers don't trigger properly

Solution

• Analyze the code and identify the root cause
• Convert all NativeFinalizer instance variables to static variables in:
  • Tree class (line 125)
  • Parser class (line 61)
  • CancelToken class (line 113)
  • TreeCursor class (line 145)
  • Query class (line 156)
  • QueryCursor class (line 246)
• Fixed bug in QueryCursor: was using ts_query_delete instead of ts_query_cursor_delete
• Verified all changes are syntactically correct
• Updated CHANGELOG.md with version 0.2.1
• Bumped version in pubspec.yaml to 0.2.1

Expected Result

Memory usage when parsing 50k files should now:

• Peak at ~1.3 GB (down from 15 GB)
• Match the manual deletion behavior
• Automatically free memory as Tree objects go out of scope

The fix ensures one NativeFinalizer per class type, allowing efficient memory management by the Dart runtime.

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[TimWhiting]

@copilot
I don't know that this is the actual root cause of the user's issue, but it seems like a step in the right direction. I've removed the Fixes PR# description. Please update the changelog, and bump the version.

[Copilot]

@copilot
I don't know that this is the actual root cause of the user's issue, but it seems like a step in the right direction. I've removed the Fixes PR# description. Please update the changelog, an...

Updated the changelog and bumped version to 0.2.1 in commit 1b26f4f.