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/project/src/git.rs

@@ -8,8 +8,7 @@ use git::{
     status::{GitSummary, TrackedSummary},
 };
 use gpui::{
-    AppContext, Context as _, EventEmitter, Model, ModelContext, SharedString, Subscription,
-    WeakModel,
+    App, AppContext as _, Context, Entity, EventEmitter, SharedString, Subscription, WeakEntity,
 };
 use language::{Buffer, LanguageRegistry};
 use settings::WorktreeId;
@@ -28,11 +27,11 @@ pub struct GitState {
 
 #[derive(Clone)]
 pub struct RepositoryHandle {
-    git_state: WeakModel<GitState>,
+    git_state: WeakEntity<GitState>,
     worktree_id: WorktreeId,
     repository_entry: RepositoryEntry,
     git_repo: Arc<dyn GitRepository>,
-    commit_message: Model<Buffer>,
+    commit_message: Entity<Buffer>,
     update_sender: mpsc::UnboundedSender<(Message, mpsc::Sender<anyhow::Error>)>,
 }
 
@@ -67,9 +66,9 @@ impl EventEmitter<Event> for GitState {}
 
 impl GitState {
     pub fn new(
-        worktree_store: &Model<WorktreeStore>,
+        worktree_store: &Entity<WorktreeStore>,
         languages: Arc<LanguageRegistry>,
-        cx: &mut ModelContext<'_, Self>,
+        cx: &mut Context<'_, Self>,
     ) -> Self {
         let (update_sender, mut update_receiver) =
             mpsc::unbounded::<(Message, mpsc::Sender<anyhow::Error>)>();
@@ -115,9 +114,9 @@ impl GitState {
 
     fn on_worktree_store_event(
         &mut self,
-        worktree_store: Model<WorktreeStore>,
+        worktree_store: Entity<WorktreeStore>,
         _event: &WorktreeStoreEvent,
-        cx: &mut ModelContext<'_, Self>,
+        cx: &mut Context<'_, Self>,
     ) {
         // TODO inspect the event
 
@@ -150,7 +149,7 @@ impl GitState {
                             existing_handle.repository_entry = repo.clone();
                             existing_handle
                         } else {
-                            let commit_message = cx.new_model(|cx| Buffer::local("", cx));
+                            let commit_message = cx.new(|cx| Buffer::local("", cx));
                             cx.spawn({
                                 let commit_message = commit_message.downgrade();
                                 let languages = self.languages.clone();
@@ -194,7 +193,7 @@ impl GitState {
 }
 
 impl RepositoryHandle {
-    pub fn display_name(&self, project: &Project, cx: &AppContext) -> SharedString {
+    pub fn display_name(&self, project: &Project, cx: &App) -> SharedString {
         maybe!({
             let path = self.unrelativize(&"".into())?;
             Some(
@@ -209,7 +208,7 @@ impl RepositoryHandle {
         .unwrap_or("".into())
     }
 
-    pub fn activate(&self, cx: &mut AppContext) {
+    pub fn activate(&self, cx: &mut App) {
         let Some(git_state) = self.git_state.upgrade() else {
             return;
         };
@@ -236,7 +235,7 @@ impl RepositoryHandle {
         Some((self.worktree_id, path).into())
     }
 
-    pub fn commit_message(&self) -> Model<Buffer> {
+    pub fn commit_message(&self) -> Entity<Buffer> {
         self.commit_message.clone()
     }
 
@@ -304,7 +303,7 @@ impl RepositoryHandle {
         self.repository_entry.status_summary().index != TrackedSummary::UNCHANGED
     }
 
-    pub fn can_commit(&self, commit_all: bool, cx: &AppContext) -> bool {
+    pub fn can_commit(&self, commit_all: bool, cx: &App) -> bool {
         return self
             .commit_message
             .read(cx)
@@ -314,7 +313,7 @@ impl RepositoryHandle {
             && (commit_all || self.have_staged_changes());
     }
 
-    pub fn commit(&self, mut err_sender: mpsc::Sender<anyhow::Error>, cx: &mut AppContext) {
+    pub fn commit(&self, mut err_sender: mpsc::Sender<anyhow::Error>, cx: &mut App) {
         let message = self.commit_message.read(cx).as_rope().clone();
         let result = self.update_sender.unbounded_send((
             Message::Commit(self.git_repo.clone(), message),
@@ -335,7 +334,7 @@ impl RepositoryHandle {
         });
     }
 
-    pub fn commit_all(&self, mut err_sender: mpsc::Sender<anyhow::Error>, cx: &mut AppContext) {
+    pub fn commit_all(&self, mut err_sender: mpsc::Sender<anyhow::Error>, cx: &mut App) {
         let to_stage = self
             .repository_entry
             .status()