Summary

Replace the polling-based input system with a proper platform abstraction layer that provides event-driven console I/O. This addresses Windows compatibility issues and eliminates the 10ms input latency caused by the current polling architecture.

Problem

The current ConsoleInputSource uses a 10ms polling loop with Console.KeyAvailable + Console.ReadKey. This is an architectural flaw that causes:

1. Input latency - Minimum 10ms delay before input is processed
2. CPU usage - Constant polling even when idle
3. Windows issues - No explicit VT100 enablement, causing rendering problems in some terminals (Cmder/ConEmu)
4. No resize signals - Terminal resize is also polled instead of signal-based (Unix)

Solution

Create an IPlatformConsole interface with platform-specific implementations:

• WindowsConsole - P/Invoke for SetConsoleMode (VT100), ReadConsoleInputW (event-driven)
• UnixConsole - termios raw mode, select()/poll() on stdin, SIGWINCH signal handler
• FallbackConsole - Current polling logic for unsupported platforms

Child Issues

• Define IPlatformConsole interface and console event types #78 - Define IPlatformConsole interface and console event types
• Implement Windows console with P/Invoke (VT100 + event-driven input) #79 - Implement Windows console with P/Invoke (VT100 + event-driven input)
• Implement Unix console with termios and SIGWINCH #80 - Implement Unix console with termios and SIGWINCH
• Implement fallback console (polling) for unsupported platforms #81 - Implement fallback console (polling) for unsupported platforms
• Add global key interceptor to TerminaApplication #82 - Add global key interceptor to TerminaApplication
• Wire up platform console and deprecate ConsoleInputSource #83 - Wire up platform console and deprecate ConsoleInputSource

Acceptance Criteria

• No polling-based input on Windows and Unix
• VT100 processing explicitly enabled on Windows
• Ctrl+Q works to quit applications regardless of focused component
• Terminal resize detected via signals on Unix
• Input latency reduced to near-zero
• Existing tests pass
• Works on Windows Terminal, Cmder (best effort), Linux terminals, macOS Terminal