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/notifications/src/notification_store.rs

@@ -1,31 +1,29 @@
-use anyhow::{Context, Result};
+use anyhow::{Context as _, Result};
 use channel::{ChannelMessage, ChannelMessageId, ChannelStore};
 use client::{ChannelId, Client, UserStore};
 use collections::HashMap;
 use db::smol::stream::StreamExt;
-use gpui::{
-    AppContext, AsyncAppContext, Context as _, EventEmitter, Global, Model, ModelContext, Task,
-};
+use gpui::{App, AppContext as _, AsyncAppContext, Context, Entity, EventEmitter, Global, Task};
 use rpc::{proto, Notification, TypedEnvelope};
 use std::{ops::Range, sync::Arc};
 use sum_tree::{Bias, SumTree};
 use time::OffsetDateTime;
 use util::ResultExt;
 
-pub fn init(client: Arc<Client>, user_store: Model<UserStore>, cx: &mut AppContext) {
-    let notification_store = cx.new_model(|cx| NotificationStore::new(client, user_store, cx));
+pub fn init(client: Arc<Client>, user_store: Entity<UserStore>, cx: &mut App) {
+    let notification_store = cx.new(|cx| NotificationStore::new(client, user_store, cx));
     cx.set_global(GlobalNotificationStore(notification_store));
 }
 
-struct GlobalNotificationStore(Model<NotificationStore>);
+struct GlobalNotificationStore(Entity<NotificationStore>);
 
 impl Global for GlobalNotificationStore {}
 
 pub struct NotificationStore {
     client: Arc<Client>,
-    user_store: Model<UserStore>,
+    user_store: Entity<UserStore>,
     channel_messages: HashMap<u64, ChannelMessage>,
-    channel_store: Model<ChannelStore>,
+    channel_store: Entity<ChannelStore>,
     notifications: SumTree<NotificationEntry>,
     loaded_all_notifications: bool,
     _watch_connection_status: Task<Option<()>>,
@@ -72,15 +70,11 @@ struct Count(usize);
 struct NotificationId(u64);
 
 impl NotificationStore {
-    pub fn global(cx: &AppContext) -> Model<Self> {
+    pub fn global(cx: &App) -> Entity<Self> {
         cx.global::<GlobalNotificationStore>().0.clone()
     }
 
-    pub fn new(
-        client: Arc<Client>,
-        user_store: Model<UserStore>,
-        cx: &mut ModelContext<Self>,
-    ) -> Self {
+    pub fn new(client: Arc<Client>, user_store: Entity<UserStore>, cx: &mut Context<Self>) -> Self {
         let mut connection_status = client.status();
         let watch_connection_status = cx.spawn(|this, mut cx| async move {
             while let Some(status) = connection_status.next().await {
@@ -155,7 +149,7 @@ impl NotificationStore {
     pub fn load_more_notifications(
         &self,
         clear_old: bool,
-        cx: &mut ModelContext<Self>,
+        cx: &mut Context<Self>,
     ) -> Option<Task<Result<()>>> {
         if self.loaded_all_notifications && !clear_old {
             return None;
@@ -191,19 +185,19 @@ impl NotificationStore {
         }))
     }
 
-    fn handle_connect(&mut self, cx: &mut ModelContext<Self>) -> Option<Task<Result<()>>> {
+    fn handle_connect(&mut self, cx: &mut Context<Self>) -> Option<Task<Result<()>>> {
         self.notifications = Default::default();
         self.channel_messages = Default::default();
         cx.notify();
         self.load_more_notifications(true, cx)
     }
 
-    fn handle_disconnect(&mut self, cx: &mut ModelContext<Self>) {
+    fn handle_disconnect(&mut self, cx: &mut Context<Self>) {
         cx.notify()
     }
 
     async fn handle_new_notification(
-        this: Model<Self>,
+        this: Entity<Self>,
         envelope: TypedEnvelope<proto::AddNotification>,
         cx: AsyncAppContext,
     ) -> Result<()> {
@@ -221,7 +215,7 @@ impl NotificationStore {
     }
 
     async fn handle_delete_notification(
-        this: Model<Self>,
+        this: Entity<Self>,
         envelope: TypedEnvelope<proto::DeleteNotification>,
         mut cx: AsyncAppContext,
     ) -> Result<()> {
@@ -232,7 +226,7 @@ impl NotificationStore {
     }
 
     async fn handle_update_notification(
-        this: Model<Self>,
+        this: Entity<Self>,
         envelope: TypedEnvelope<proto::UpdateNotification>,
         mut cx: AsyncAppContext,
     ) -> Result<()> {
@@ -262,7 +256,7 @@ impl NotificationStore {
     }
 
     async fn add_notifications(
-        this: Model<Self>,
+        this: Entity<Self>,
         notifications: Vec<proto::Notification>,
         options: AddNotificationsOptions,
         mut cx: AsyncAppContext,
@@ -366,7 +360,7 @@ impl NotificationStore {
         &mut self,
         notifications: impl IntoIterator<Item = (u64, Option<NotificationEntry>)>,
         is_new: bool,
-        cx: &mut ModelContext<'_, NotificationStore>,
+        cx: &mut Context<'_, NotificationStore>,
     ) {
         let mut cursor = self.notifications.cursor::<(NotificationId, Count)>(&());
         let mut new_notifications = SumTree::default();
@@ -425,7 +419,7 @@ impl NotificationStore {
         &mut self,
         notification: Notification,
         response: bool,
-        cx: &mut ModelContext<Self>,
+        cx: &mut Context<Self>,
     ) {
         match notification {
             Notification::ContactRequest { sender_id } => {