Add Kitty Keyboard Protocol support (Phase 1 + Phase 2 start)

[tig]

Summary

• Phase 1 complete: Kitty keyboard protocol detection, enable/disable lifecycle, CSI u parser, and compatibility mapping into the current Key model
• Phase 2 started: Plan updated with detailed implementation steps for rich keyboard event model (KeyUp, KeyEventType, standalone modifier events)
• Merged latest v2_develop and resolved all conflicts

Relates to #4809

What's included

Phase 1 — Compatibility plumbing

• Kitty protocol query/enable/disable constants in EscSeqUtils
• KittyKeyboardProtocolDetector with structured results
• Startup detection wiring in MainLoopCoordinator
• AnsiOutput enable/disable lifecycle with degraded mode safety
• KittyKeyboardPattern parser (checked before generic CSI patterns)
• Compatibility mapping: printable keys, modifiers, navigation, editing, function keys through F24
• Comprehensive tests: detector, parser, input, lifecycle, and startup

Merge resolution

• Resolved 8 merge conflicts from v2_develop integration
• Fixed Trace ambiguity (System.Diagnostics.Trace vs Terminal.Gui.Tracing.Trace)
• Adopted v2_develop's using Terminal.Gui.Tracing pattern and primary constructor style

Test plan

• dotnet build --no-restore passes
• dotnet test --project Tests/UnitTestsParallelizable --no-build — all pass
• dotnet test --project Tests/UnitTests --no-build — all pass
• Manual testing with kitty-capable terminal (Windows Terminal Preview 1.25+)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds Phase-1 kitty keyboard protocol support to the ANSI driver (probe → enable → parse CSI u → disable on shutdown) and introduces a centralized “real terminal attached” detection/gating mechanism to make driver I/O deterministic in CI/test harnesses.

Changes:

• Implement kitty keyboard protocol detection, enable/disable emission, and CSI u parsing with a Phase-1 compatibility mapping into the current Key model.
• Centralize terminal-attachment detection in Driver.IsAttachedToTerminal(...) and use DisableRealDriverIO=1 to force degraded/no-op driver I/O in tests/CI.
• Add/expand targeted unit + integration-style tests and wire CI workflows/runsettings to set DisableRealDriverIO.

Reviewed changes

Copilot reviewed 40 out of 40 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
plans/pr-4810-body.md	PR body plan/summary for kitty keyboard Phase 1.
plans/kitty-keyboard-protocol-plan.md	Detailed implementation plan and phased design notes.
Tests/test.runsettings	Sets DisableRealDriverIO=1 for test runs via runsettings.
Tests/Directory.Build.props	Points test projects at test.runsettings.
Tests/UnitTestsParallelizable/Drivers/Windows/WindowsInputOutputTests.cs	Adds test asserting IsAttachedToTerminal is false in harness.
Tests/UnitTestsParallelizable/Drivers/Unix/UnixInputOutputTests.cs	Adds test asserting IsAttachedToTerminal is false in harness.
Tests/UnitTestsParallelizable/Drivers/Dotnet/NetInputOutputTests.cs	Adds test asserting IsAttachedToTerminal is false in harness.
Tests/UnitTestsParallelizable/Drivers/AnsiHandling/KittyKeyboardProtocolDetectorTests.cs	New tests for kitty protocol detection + response parsing.
Tests/UnitTestsParallelizable/Drivers/AnsiHandling/AnsiKeyboardParserTests.cs	Adds kitty CSI u parsing cases (printable, nav/edit, function keys).
Tests/UnitTestsParallelizable/Drivers/AnsiDriver/AnsiInputTestableTests.cs	Integration-style tests injecting kitty sequences char-by-char.
Tests/UnitTestsParallelizable/Drivers/Ansi/AnsiTerminalHelperTests.cs	New tests verifying env var propagation + IsAttachedToTerminal gating.
Tests/UnitTestsParallelizable/Drivers/Ansi/AnsiInputOutputTests.cs	Adds low-level kitty enable/disable lifecycle assertions for AnsiOutput.
Tests/UnitTestsParallelizable/Application/MainLoopCoordinatorTests.cs	Adds startup wiring test validating kitty probe/enable/disable flow.
Tests/UnitTests/Application/MainLoopCoordinatorTests.cs	Removes/moves prior test content (file now minimal).
Tests/IntegrationTests/FluentTests/TestContextTests.cs	Adds env-var gating assertions in integration tests.
Terminal.sln.DotSettings	Adds csbi to dictionary (spellchecker exception).
Terminal.Gui/Drivers/WindowsDriver/WindowsOutput.cs	Gates Windows output operations on terminal attachment; refactors formatting; adds fallback sizing behavior.
Terminal.Gui/Drivers/WindowsDriver/WindowsInput.cs	Gates Windows input initialization on terminal attachment; refactors P/Invoke formatting.
Terminal.Gui/Drivers/UnixDriver/UnixTerminalHelper.cs	Uses Driver.IsAttachedToTerminal instead of ANSI helper for suspend gating.
Terminal.Gui/Drivers/UnixDriver/UnixOutput.cs	Adds terminal-attachment gating for output methods and sizing fallback.
Terminal.Gui/Drivers/UnixDriver/UnixInput.cs	Adds terminal-attachment gating; reorganizes init flow; minor cleanups.
Terminal.Gui/Drivers/UnixDriver/UnixIOHelper.cs	Formatting/interop signature tweaks; small logic/style improvements.
Terminal.Gui/Drivers/Output/OutputBase.cs	Adds cached IsAttachedToTerminal; refactors properties/formatting; minor logic reshaping.
Terminal.Gui/Drivers/Input/InputImpl.cs	Adds cached IsAttachedToTerminal for input implementations.
Terminal.Gui/Drivers/DriverImpl.cs	Persists kitty protocol detection/enabled flags on driver instance.
Terminal.Gui/Drivers/Driver.cs	Adds centralized IsAttachedToTerminal and env var override; refactors Force16Colors.
Terminal.Gui/Drivers/DotNetDriver/NetOutput.cs	Adds terminal-attachment gating in ctor/write/size; minor refactors.
Terminal.Gui/Drivers/DotNetDriver/NetInput.cs	Adds terminal-attachment gating and minor refactors.
Terminal.Gui/Drivers/AnsiHandling/KittyKeyboardProtocolDetector.cs	New detector + KittyKeyboardProtocolResult and response parsing.
Terminal.Gui/Drivers/AnsiHandling/KittyKeyboardPattern.cs	New CSI u parser pattern mapping kitty codes/modifiers into Key.
Terminal.Gui/Drivers/AnsiHandling/EscSeqUtils/EscSeqUtils.cs	Adds kitty query/enable/disable sequences + Phase-1 flag constant(s).
Terminal.Gui/Drivers/AnsiHandling/AnsiResponseExpectation.cs	Refactors expectation matching to avoid regex and support kitty query metadata.
Terminal.Gui/Drivers/AnsiHandling/AnsiKeyboardParser.cs	Registers kitty pattern ahead of broader CSI patterns.
Terminal.Gui/Drivers/AnsiDriver/AnsiTerminalHelper.cs	Removes duplicated terminal-attachment detection (now centralized).
Terminal.Gui/Drivers/AnsiDriver/AnsiOutput.cs	Adds kitty enable/disable lifecycle on output; integrates degraded-mode gating adjustments.
Terminal.Gui/Drivers/AnsiDriver/AnsiInput.cs	Switches to centralized terminal-attachment gating in init paths.
Terminal.Gui/App/MainLoop/MainLoopCoordinator.cs	Wires kitty protocol detection and conditional enable into driver startup.
.github/workflows/unit-tests.yml	Sets DisableRealDriverIO=1 in CI for unit tests.
.github/workflows/stress-tests.yml	Sets DisableRealDriverIO=1 in CI for stress tests.
.github/workflows/integration-tests.yml	Sets DisableRealDriverIO=1 in CI for integration tests.

Comments suppressed due to low confidence (1)

Terminal.Gui/Drivers/DotNetDriver/NetOutput.cs:175

• SetCursorPositionImpl writes directly to Console.Out via EscSeqUtils.CSI_WriteCursorPosition even when IsAttachedToTerminal is false, bypassing the new degraded-mode gating in Write(...). Add an IsAttachedToTerminal guard (or route through Write(...)) so cursor movement is a true no-op when real driver I/O is disabled/redirected.

    /// <inheritdoc/>
    protected override bool SetCursorPositionImpl (int col, int row)
    {
        if (_currentCursor.Position is { } && _currentCursor.Position.Value.X == col && _currentCursor.Position.Value.Y == row)
        {
            return false;
        }

        if (_isWinPlatform)
        {
            try
            {
                Console.SetCursorPosition (col, row);
            }
            catch
            {
                // Could happen that the windows is still resizing and the col is bigger than Console.WindowWidth.
            }

            return true;
        }

        // + 1 is needed because non-Windows is based on 1 instead of 0 and
        // Console.CursorTop/CursorLeft isn't reliable.
        EscSeqUtils.CSI_WriteCursorPosition (Console.Out, row + 1, col + 1);

        return true;

[BDisp]

Fantastic. Very good implementation.