Eliminate GPUI View, ViewContext, and WindowContext types (#22632)

There's still a bit more work to do on this, but this PR is compiling
(with warnings) after eliminating the key types. When the tasks below
are complete, this will be the new narrative for GPUI:

- `Entity<T>` - This replaces `View<T>`/`Model<T>`. It represents a unit
of state, and if `T` implements `Render`, then `Entity<T>` implements
`Element`.
- `&mut App` This replaces `AppContext` and represents the app.
- `&mut Context<T>` This replaces `ModelContext` and derefs to `App`. It
is provided by the framework when updating an entity.
- `&mut Window` Broken out of `&mut WindowContext` which no longer
exists. Every method that once took `&mut WindowContext` now takes `&mut
Window, &mut App` and every method that took `&mut ViewContext<T>` now
takes `&mut Window, &mut Context<T>`

Not pictured here are the two other failed attempts. It's been quite a
month!

Tasks:

- [x] Remove `View`, `ViewContext`, `WindowContext` and thread through
`Window`
- [x] [@cole-miller @mikayla-maki] Redraw window when entities change
- [x] [@cole-miller @mikayla-maki] Get examples and Zed running
- [x] [@cole-miller @mikayla-maki] Fix Zed rendering
- [x] [@mikayla-maki] Fix todo! macros and comments
- [x] Fix a bug where the editor would not be redrawn because of view
caching
- [x] remove publicness window.notify() and replace with
`AppContext::notify`
- [x] remove `observe_new_window_models`, replace with
`observe_new_models` with an optional window
- [x] Fix a bug where the project panel would not be redrawn because of
the wrong refresh() call being used
- [x] Fix the tests
- [x] Fix warnings by eliminating `Window` params or using `_`
- [x] Fix conflicts
- [x] Simplify generic code where possible
- [x] Rename types
- [ ] Update docs

### issues post merge

- [x] Issues switching between normal and insert mode
- [x] Assistant re-rendering failure
- [x] Vim test failures
- [x] Mac build issue



Release Notes:

- N/A

---------

Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Cole Miller <cole@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Joseph <joseph@zed.dev>
Co-authored-by: max <max@zed.dev>
Co-authored-by: Michael Sloan <michael@zed.dev>
Co-authored-by: Mikayla Maki <mikaylamaki@Mikaylas-MacBook-Pro.local>
Co-authored-by: Mikayla <mikayla.c.maki@gmail.com>
Co-authored-by: joão <joao@zed.dev>

crates/ui_input/src/ui_input.rs

@@ -6,7 +6,7 @@
 //!
 
 use editor::{Editor, EditorElement, EditorStyle};
-use gpui::{AppContext, FocusHandle, FocusableView, FontStyle, Hsla, TextStyle, View};
+use gpui::{App, Entity, FocusHandle, Focusable, FontStyle, Hsla, TextStyle};
 use settings::Settings;
 use theme::ThemeSettings;
 use ui::prelude::*;
@@ -24,9 +24,9 @@ pub struct TextFieldStyle {
     border_color: Hsla,
 }
 
-/// A Text Field view that can be used to create text fields like search inputs, form fields, etc.
+/// A Text Field that can be used to create text fields like search inputs, form fields, etc.
 ///
-/// It wraps a single line [`Editor`] view and allows for common field properties like labels, placeholders, icons, etc.
+/// It wraps a single line [`Editor`] and allows for common field properties like labels, placeholders, icons, etc.
 pub struct TextField {
     /// An optional label for the text field.
     ///
@@ -34,10 +34,10 @@ pub struct TextField {
     label: SharedString,
     /// The placeholder text for the text field.
     placeholder: SharedString,
-    /// Exposes the underlying [`View<Editor>`] to allow for customizing the editor beyond the provided API.
+    /// Exposes the underlying [`Model<Editor>`] to allow for customizing the editor beyond the provided API.
     ///
     /// This likely will only be public in the short term, ideally the API will be expanded to cover necessary use cases.
-    pub editor: View<Editor>,
+    pub editor: Entity<Editor>,
     /// An optional icon that is displayed at the start of the text field.
     ///
     /// For example, a magnifying glass icon in a search field.
@@ -48,22 +48,23 @@ pub struct TextField {
     disabled: bool,
 }
 
-impl FocusableView for TextField {
-    fn focus_handle(&self, cx: &AppContext) -> FocusHandle {
+impl Focusable for TextField {
+    fn focus_handle(&self, cx: &App) -> FocusHandle {
         self.editor.focus_handle(cx)
     }
 }
 
 impl TextField {
     pub fn new(
-        cx: &mut WindowContext,
+        window: &mut Window,
+        cx: &mut App,
         label: impl Into<SharedString>,
         placeholder: impl Into<SharedString>,
     ) -> Self {
         let placeholder_text = placeholder.into();
 
-        let editor = cx.new_view(|cx| {
-            let mut input = Editor::single_line(cx);
+        let editor = cx.new(|cx| {
+            let mut input = Editor::single_line(window, cx);
             input.set_placeholder_text(placeholder_text.clone(), cx);
             input
         });
@@ -88,19 +89,19 @@ impl TextField {
         self
     }
 
-    pub fn set_disabled(&mut self, disabled: bool, cx: &mut ViewContext<Self>) {
+    pub fn set_disabled(&mut self, disabled: bool, cx: &mut Context<Self>) {
         self.disabled = disabled;
         self.editor
             .update(cx, |editor, _| editor.set_read_only(disabled))
     }
 
-    pub fn editor(&self) -> &View<Editor> {
+    pub fn editor(&self) -> &Entity<Editor> {
         &self.editor
     }
 }
 
 impl Render for TextField {
-    fn render(&mut self, cx: &mut ViewContext<Self>) -> impl IntoElement {
+    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
         let settings = ThemeSettings::get_global(cx);
         let theme_color = cx.theme().colors();