Fixes #5369 - BREAKING CHANGE - Move IAcceptTarget to Terminal.Gui.Input namespace

[Copilot]

Summary

Moves IAcceptTarget from namespace Terminal.Gui to namespace Terminal.Gui.Input to co-locate it with related command/input types (Command, CommandBinding, ICommandContext, etc.).

Breaking Change

This is a binary-breaking namespace move. Any downstream code referencing Terminal.Gui.IAcceptTarget in compiled IL will fail with TypeLoadException unless recompiled.

Changes

• Terminal.Gui/Input/IAcceptTarget.cs — namespace Terminal.Gui; → namespace Terminal.Gui.Input;
• docfx/README.md, docfx/docs/command.md, docfx/docs/command-diagrams.md — Updated xref/doc references
• Tests/UnitTestsParallelizable/ViewBase/ViewCommandTests.cs — Namespace assertion test

Cross-Dependency Coordination Plan (TG ↔ TG.Editor)

Lessons Learned from #5372 / #5378 / #5386

The Bind/PlatformKeyBinding namespace move required a painful 3-PR dance:

1. PR Closes #5369: Cannot move Bind/PlatformKeyBinding to Input namespace (binary compat blocker) #5372 discovered the binary compat blocker (Editor's compiled IL referenced old namespace)
2. PR Fixes #5369. Move Bind and PlatformKeyBinding to Terminal.Gui.Input namespace #5378 worked around it with a local_packages/ hack (local .nupkg of Editor built against new namespace)
3. PR Fixes #5380. Remove local Terminal.Gui.Editor package hack #5386 cleaned up the hack after a real Editor release was published

Why This PR Is Lower Risk

IAcceptTarget is not referenced in the gui-cs/Editor source or compiled package (verified via GitHub code search). The Editor package will not throw TypeLoadException from this move alone.

Release Sequencing Plan

This PR will not be released until after PR #5371 (View.Text CWP / non-virtual — another breaking change) is also merged, so we batch both into a single .minor version bump.

Step-by-step merge & release order:

┌─────────────────────────────────────────────────────────────────────┐
│ Phase 1: Merge breaking changes into TG develop                     │
├─────────────────────────────────────────────────────────────────────┤
│ 1. Merge PR #5371 (View.Text CWP breaking change)                  │
│ 2. Merge PR #5395 (this PR — IAcceptTarget namespace move)          │
│ 3. Run full CI on develop (all test projects green)                 │
└─────────────────────────────────────────────────────────────────────┘
         │
         ▼
┌─────────────────────────────────────────────────────────────────────┐
│ Phase 2: Pre-release validation in TG.Editor                        │
├─────────────────────────────────────────────────────────────────────┤
│ 4. In gui-cs/Editor, create branch: `update-tg-2.5.0`              │
│    - Bump TerminalGuiVersion property to new TG prerelease version  │
│    - Add `using Terminal.Gui.Input;` if any file needs IAcceptTarget│
│      (currently none — but verify at merge time)                    │
│    - Adapt to View.Text non-virtual changes (#5371) if affected     │
│    - Run Editor CI against TG develop nightly/prerelease feed       │
│ 5. Open PR in gui-cs/Editor — CI must pass                          │
└─────────────────────────────────────────────────────────────────────┘
         │
         ▼
┌─────────────────────────────────────────────────────────────────────┐
│ Phase 3: Coordinated release                                        │
├─────────────────────────────────────────────────────────────────────┤
│ 6. Tag & publish Terminal.Gui 2.5.0 to NuGet                        │
│ 7. Merge Editor PR (bumps to TG ≥ 2.5.0)                           │
│ 8. Tag & publish Terminal.Gui.Editor (next version) to NuGet        │
│ 9. Back in TG: bump `Terminal.Gui.Editor` PackageVersion in         │
│    Directory.Packages.props to the new Editor release               │
│ 10. Verify TG CI (NativeAot smoke test exercises Editor)            │
└─────────────────────────────────────────────────────────────────────┘

No Local Package Hack Needed This Time

Unlike the Bind/PlatformKeyBinding move (#5378), we do not need a local_packages/ workaround because:

• IAcceptTarget has no compiled references in Editor's IL
• The Editor's TerminalGuiVersion pin (2.4.0) will simply be bumped to ≥ 2.5.0 after TG releases

CI/CD Monitoring Checkpoints

Checkpoint	What to verify	Repo
After Phase 1 merge	All TG test projects pass on develop	gui-cs/Terminal.Gui
Editor PR opened	Editor builds & tests pass against TG prerelease	gui-cs/Editor
After TG 2.5.0 tag	NuGet package published, GH release created	gui-cs/Terminal.Gui
After Editor release	Editor NuGet published, depends on TG ≥ 2.5.0	gui-cs/Editor
Final TG update	NativeAot smoke test passes with new Editor pkg	gui-cs/Terminal.Gui

Risk Mitigation

• If Editor gains IAcceptTarget usage before merge: Add using Terminal.Gui.Input; to affected Editor files in the Phase 2 PR
• If CI breaks after TG release but before Editor release: The existing TG.Editor 2.4.1 remains functional (no IL reference to IAcceptTarget) — no user-facing breakage
• Rollback: If issues arise, revert this PR's commit on develop before tagging — the namespace move is a single-commit change

Verification

• ✅ Full solution builds (0 errors)
• ✅ All parallelizable tests pass
• ✅ NativeAot example builds successfully
• ✅ No new warnings introduced

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui
• My code follows the Terminal.Gui library design guidelines
• I ran dotnet test before commit
• I have made corresponding changes to the API documentation (using /// style comments)
• My changes generate no new warnings
• I have checked my code and corrected any poor grammar or misspellings
• I conducted basic QA to assure all features are working

[Copilot]

Pull request overview

Moves IAcceptTarget into the Terminal.Gui.Input namespace to align it with the rest of the command/input API surface, and updates docs/tests to reflect the new UID/namespace.

Changes:

• Moved IAcceptTarget from Terminal.Gui → Terminal.Gui.Input.
• Updated DocFX docs/xref UIDs referencing IAcceptTarget to the new namespace.
• Added a unit test asserting IAcceptTarget’s namespace to prevent regressions.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
Terminal.Gui/Input/IAcceptTarget.cs	Changes the interface namespace to Terminal.Gui.Input.
docfx/README.md	Updates namespace prefix/UID documentation for IAcceptTarget.
docfx/docs/command.md	Updates xref references from Terminal.Gui.IAcceptTarget to Terminal.Gui.Input.IAcceptTarget.
docfx/docs/command-diagrams.md	Updates xref reference in diagrams text to the new namespace.
Tests/UnitTestsParallelizable/ViewBase/ViewCommandTests.cs	Adds a test asserting IAcceptTarget is in Terminal.Gui.Input.