Fixes #4317 - Refactor Application.Mouse for decoupling and parallelism (#4318)

* Initial plan

* Refactor Application.Mouse - Create IMouse interface and Mouse implementation

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Add enhanced documentation for Application.Mouse property

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Add parallelizable unit tests for IMouse interface

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Refactor Application.Mouse for decoupling and parallelism

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Move HandleMouseGrab method to IMouseGrabHandler interface

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Add parallelizable tests for IMouse and IMouseGrabHandler interfaces

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Add MouseEventRoutingTests - 27 parallelizable tests for View mouse event handling

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Fix terminology: Replace parent/child with superView/subView in MouseEventRoutingTests

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Fix coding standards: Use explicit types and target-typed new() in test files

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Update coding standards documentation with explicit var and target-typed new() guidance

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Refactor Application classes and improve maintainability

Refactored `Sixel` property to be immutable, enhancing thread safety.
Cleaned up `ApplicationImpl` by removing redundant fields, restructuring
methods (`CreateDriver`, `CreateSubcomponents`), and improving exception
handling. Updated `Run<T>` and `Shutdown` methods for consistency.

Standardized logging/debugging messages and fixed formatting issues.
Reorganized `IApplication` interface, added detailed XML documentation,
and grouped related methods logically.

Performed general code cleanup, including fixing typos, improving
readability, and removing legacy/unnecessary code to reduce technical debt.

* Code cleanup

* Remove unreferenced LayoutAndDraw method from ApplicationImpl

* Code cleanup and TODOs

- Updated namespaces to reflect the new structure.
- Added `Driver`, `Force16Colors`, and `ForceDriver` properties.
- Introduced `Sixel` collection for sixel image management.
- Added lifecycle methods: `GetDriverTypes`, `Shutdown`, and events.
- Refactored `Init` to support legacy and modern drivers.
- Improved driver event handling and screen abstraction.
- Updated `Run` method to align with the application lifecycle.
- Simplified `IConsoleDriver` documentation.
- Removed redundant methods and improved code readability.

* Refactor LayoutAndDraw logic for better encapsulation

Refactored `Application.Run` to delegate `LayoutAndDraw` to
`ApplicationImpl.Instance.LayoutAndDraw`, improving separation
of concerns. Renamed `forceDraw` to `forceRedraw` for clarity
and moved `LayoutAndDraw` implementation to `ApplicationImpl`.

Added a new `LayoutAndDraw` method in `ApplicationImpl` to
handle layout and drawing, including managing `TopLevels`,
handling active popovers, and refreshing the screen. Updated
the `IApplication` interface to reflect the new method and
improved its documentation.

Implemented `RequestStop` in `ApplicationImpl` and fixed
formatting inconsistencies in `Run<T>`. Added TODOs for future
refactoring to encapsulate `Top` and `TopLevels` into an
`IViewHierarchy` and move certain properties to `IApplication`.

* Refactor ApplicationImpl to enhance mouse and keyboard support

Added a new `Mouse` property to the `ApplicationImpl` class,
replacing its previous declaration, to improve mouse
functionality. Updated `MouseGrabHandler` to initialize with
a default instance of `MouseGrabHandler`.

Added comments to ensure the preservation of existing keyboard
settings (`QuitKey`, `ArrangeKey`, `NextTabKey`) for backward
compatibility. These changes enhance clarity, functionality,
and maintainability of the class.

* Merge IMouseGrabHandler into IMouse - consolidate mouse handling into single interface

Co-authored-by: tig <585482+tig@users.noreply.github.com>

* Rename Mouse to MouseImpl and Keyboard to KeyboardImpl for consistency

Co-authored-by: tig <585482+tig@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: tig <585482+tig@users.noreply.github.com>
Co-authored-by: Tig <tig@users.noreply.github.com>

.github/copilot-instructions.md

@@ -150,12 +150,44 @@ dotnet run --project Examples/UICatalog/UICatalog.csproj
 5. **Documentation is the Spec** - API docs are source of truth
 
 ### Coding Conventions
-- Use explicit types (avoid `var` except for basic types like `int`, `string`)
-- Use target-typed `new()`
+
+**⚠️ CRITICAL - These rules MUST be followed in ALL new code:**
+
+#### Type Declarations and Object Creation
+- **ALWAYS use explicit types** - Never use `var` except for basic types (`int`, `string`, `bool`, `double`, `float`, `decimal`, `char`, `byte`)
+  ```csharp
+  // ✅ CORRECT - Explicit types
+  View view = new () { Width = 10 };
+  MouseEventArgs args = new () { Position = new Point(5, 5) };
+  List<View?> views = new ();
+  var count = 0;  // OK - int is a basic type
+  var name = "test";  // OK - string is a basic type
+  
+  // ❌ WRONG - Using var for non-basic types
+  var view = new View { Width = 10 };
+  var args = new MouseEventArgs { Position = new Point(5, 5) };
+  var views = new List<View?>();
+  ```
+
+- **ALWAYS use target-typed `new()`** - Use `new ()` instead of `new TypeName()` when the type is already declared
+  ```csharp
+  // ✅ CORRECT - Target-typed new
+  View view = new () { Width = 10 };
+  MouseEventArgs args = new ();
+  
+  // ❌ WRONG - Redundant type name
+  View view = new View() { Width = 10 };
+  MouseEventArgs args = new MouseEventArgs();
+  ```
+
+#### Other Conventions
 - Follow `.editorconfig` settings (e.g., braces on new lines, spaces after keywords)
 - 4-space indentation
+- No trailing whitespace
 - See `CONTRIBUTING.md` for full guidelines
 
+**These conventions apply to ALL code - production code, test code, examples, and samples.**
+
 ## Testing Requirements
 
 ### Code Coverage
@@ -278,6 +310,8 @@ dotnet build --configuration Release --no-restore
 - ❌ Don't add tests to `UnitTests` if they can be parallelizable
 - ❌ Don't use `Application.Init` in new tests
 - ❌ Don't decrease code coverage
+- ❌ **Don't use `var` for non-basic types** (use explicit types)
+- ❌ **Don't use redundant type names with `new`** (use target-typed `new()`)
 - ❌ Don't add `var` everywhere (use explicit types)
 
 ## Additional Resources