feat: Complete Console API surface coverage for IConsole/ITerminal

[StevenTCramer]

Summary

• Adds complete System.Console API surface to IConsole and ITerminal interfaces, enabling full replacement of direct Console usage
• Mirrors all new APIs on the Terminal static facade class
• Includes comprehensive test doubles (TestConsole/TestTerminal) and unit tests

What Changed

IConsole (new members)

• Stream access: OpenStandardInput(), OpenStandardOutput(), OpenStandardError(), In, Out, Error, SetIn(), SetOut(), SetError()
• Encoding: InputEncoding, OutputEncoding
• Redirection state: IsInputRedirected, IsOutputRedirected, IsErrorRedirected
• Rich input: Read(), ReadKey() (parameterless overload)

ITerminal (new members)

• Cursor properties: CursorLeft, CursorTop, CursorVisible, CursorSize
• Window/buffer geometry: WindowHeight, WindowLeft, WindowTop, BufferWidth, BufferHeight, SetWindowSize(), SetWindowPosition(), SetBufferSize(), MoveBufferArea(), LargestWindowWidth, LargestWindowHeight
• Color state: ForegroundColor, BackgroundColor, ResetColor()
• Control/utility: Beep(), Beep(int, int), TreatControlCAsInput, Title, KeyAvailable

Terminal static class

• All new IConsole/ITerminal members mirrored as static pass-through to Instance

Test implementations

• TestConsole and TestTerminal updated with mock streams, encoding defaults, character queues, geometry defaults, beep tracking, etc.

Tests

• 8 new test files with ~160 unit tests covering all new API surface
• All existing tests continue to pass

Stats

• +5,691 lines across 28 files
• 0 build warnings
• Version bump: 1.0.0-beta.10 → 1.0.0-beta.11