test(opentui): comprehensive unit tests for native bindings

137 tests covering: module loading, RGBA helper, constants,
renderer lifecycle, optimized buffer operations (clear, fill, draw,
scissor, opacity, resize, compositing), text buffer (append, clear,
reset, defaults, tabs, highlights, memory buffers), text buffer view
(wrapping, selection, viewport, measurement), edit buffer (text ops,
cursor movement, undo/redo, line operations, word boundaries,
coordinate conversion), editor view (viewport, wrapping, selection,
visual cursor, drawing), syntax style (registration, lookup, attribute
combos, bulk styles), links (alloc, resolve, attribute packing),
hit grid, and buffer+view integration drawing.

Author: jdalton