[snowyukitty]

Fixes #1211.

BitmapData.drawScaled() and its draw() wrapper throw Not implemented on JavaScript. Add Canvas2D drawing with source cropping, smooth or nearest-neighbor scaling, default alpha compositing, and None replacement. Replacement is clipped to the destination rectangle so transparent pixels do not erase the rest of the bitmap, including when the source and destination overlap. Other blend modes are explicitly rejected, and rectangle bounds follow the existing HashLink implementation.

Add a BitmapDataDraw sample with pixel checks for transparent replacement, background preservation, overlapping self-copy, and alpha compositing. It runs through the existing sample build generator.

Validation:

• Haxe 4.3.7: haxe all.hxml from the repository root and haxe all.hxml from samples/ pass, including the new sample's JavaScript, HashLink and DirectX12 builds.
• Haxe 4.3.3 with Chromium 149 and WebKit 26.5: 11 pixel checks per browser cover both methods, cropping, offsets, smoothing, transparency, self-copy, bounds, unsupported blend modes, and context state. The unmodified base fails these checks; the candidate passes all 22.
• Chromium 149: the new sample initializes and renders successfully, including its pixel assertions.
• Firefox runtime validation was skipped after browser startup timed out in the isolated environment. HashLink/DirectX runtime rendering was not exercised.