Fixes #6311

Previously we assumed the dial was square, which isn't always the case.

Fixes #6315

I added some documentation to Input as I was learning how it worked
(and some minor tweaks, like handling reparenting better).

* Add a maxLines parameter for multiline Input.

If maxLines is 1, it's a single line Input that scrolls horizontally.
Otherwise, overflowed text wraps and scrolls vertically, taking up at
most `maxLines`.

Also fixed scrolling behavior so that the Input scrolls ensuring the
cursor is always visible.

Fixes https://github.com/flutter/flutter/issues/6271

* oops

* comments

* import

* test and RO.update fix

* constant

* fix.caretRect

Previously it implied that you had to always say lib/main.dart in the "flutter run" command.

Fixes #6283

Instead, we now interact with the system navigator via SystemNavigator.

Previously, if you focused a field, fields below it would shift down by one pixel.

This change tries to guarantee that that won't happen.

We weren't computing the bounds for composited transforms correctly. We
need to conjugate the transform by the offset in order to get the
correct paint bounds for the composited layer. We now also use the same
math in the non-composited case for consistency.

Also, don't scale the z-coordinate in RenderFittedBox.

Fixes #6293

This is needed to update an app's layout when a soft keyboard is shown

Sets a minimal baseline version for IDEs to verify a hot-reload supporting SDK.

Fixes: https://github.com/flutter/flutter-intellij/issues/293

* cleanup obtaining user home directory path
* refactor doctor and detect IntelliJ on Mac
* fix detect Flutter plugin for IntelliJ

* Switch to using PlatformPlugin instead of mojom

* Update engine.version

These changes were generated by IntelliJ.

The Skia team tells us that these go faster.

Previously, overall status was reported as good if Xcode and homebrew
were installed, even if there were issues with either of the tools. We
now report partial status if we detect issues with either installation.

This wrapper will eventually replace HostMessages.

Picks up a patched `dartdoc` (effecting, notablly, `crossdart`…)

We were missing these before.

This match switches the framework to use the semantics backend in `dart:ui`
rather than the Mojo backend.

This example is misleading because it relies on the old services model.
Let's remove it until #6263 is fixed.

Instead of reading the mojom serialization and re-inflating it, the
SemanticsDebugger now shows the SemanticsNode objects directly.

Performance improvement for https://github.com/flutter/flutter/issues/6008