Add RDPService with session lifecycle management (connect, disconnect,
input forwarding, frame retrieval) using an injected backend factory.
Implement MockBackend that generates animated test frames with a
blue-purple gradient, bouncing color-cycling rectangle, pulsing circle,
and grid overlay for canvas renderer verification on macOS without
FreeRDP. The real FreeRDP purego bindings are deferred to Windows.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Define the RDPBackend interface, RDPConfig, and FrameUpdate types that
abstract FreeRDP behind a pluggable backend. Add PixelBuffer for shared
RGBA frame management with partial-update support and dirty tracking.
Implement full 104-key US keyboard scancode map (JS KeyboardEvent.code
to RDP hardware scancodes) with extended-key detection helpers and
mouse event flag constants matching MS-RDPBCGR.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
