Each ClideCodeBlock and EditorView created its own TreeSitterService,
each allocating a WASM engine, store, parser, and cursor via FFI.
When widgets were disposed, multiple instances freeing the same
underlying native resources caused double-free corruption on startup.
Single shared instance for the app lifetime. Also fixes overlapping
tree-sitter spans that caused duplicated text in code blocks — spans
are now clipped to avoid re-emitting already-rendered characters.
Co-Authored-By: Claude <noreply@anthropic.com>
jpmschweitzerandClaude
b236ec439f