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/semantic_index/src/summary_index.rs

@@ -3,7 +3,7 @@ use arrayvec::ArrayString;
 use fs::{Fs, MTime};
 use futures::{stream::StreamExt, TryFutureExt};
 use futures_batch::ChunksTimeoutStreamExt;
-use gpui::{AppContext, Model, Task};
+use gpui::{App, Entity, Task};
 use heed::{
     types::{SerdeBincode, Str},
     RoTxn,
@@ -79,7 +79,7 @@ struct SummarizeFiles {
 }
 
 pub struct SummaryIndex {
-    worktree: Model<Worktree>,
+    worktree: Entity<Worktree>,
     fs: Arc<dyn Fs>,
     db_connection: heed::Env,
     file_digest_db: heed::Database<Str, SerdeBincode<FileDigest>>, // Key: file path. Val: BLAKE3 digest of its contents.
@@ -100,7 +100,7 @@ struct MightNeedSummaryFiles {
 
 impl SummaryIndex {
     pub fn new(
-        worktree: Model<Worktree>,
+        worktree: Entity<Worktree>,
         fs: Arc<dyn Fs>,
         db_connection: heed::Env,
         file_digest_db: heed::Database<Str, SerdeBincode<FileDigest>>,
@@ -129,7 +129,7 @@ impl SummaryIndex {
     pub fn index_entries_changed_on_disk(
         &self,
         is_auto_available: bool,
-        cx: &AppContext,
+        cx: &App,
     ) -> impl Future<Output = Result<()>> {
         let start = Instant::now();
         let backlogged;
@@ -192,7 +192,7 @@ impl SummaryIndex {
         &mut self,
         updated_entries: UpdatedEntriesSet,
         is_auto_available: bool,
-        cx: &AppContext,
+        cx: &App,
     ) -> impl Future<Output = Result<()>> {
         let start = Instant::now();
         let backlogged;
@@ -249,7 +249,7 @@ impl SummaryIndex {
     fn check_summary_cache(
         &self,
         might_need_summary: channel::Receiver<UnsummarizedFile>,
-        cx: &AppContext,
+        cx: &App,
     ) -> NeedsSummary {
         let db_connection = self.db_connection.clone();
         let db = self.summary_db;
@@ -286,7 +286,7 @@ impl SummaryIndex {
         }
     }
 
-    fn scan_entries(&self, worktree: Snapshot, cx: &AppContext) -> Backlogged {
+    fn scan_entries(&self, worktree: Snapshot, cx: &App) -> Backlogged {
         let (tx, rx) = channel::bounded(512);
         let db_connection = self.db_connection.clone();
         let digest_db = self.file_digest_db;
@@ -360,7 +360,7 @@ impl SummaryIndex {
         &self,
         worktree: Snapshot,
         updated_entries: UpdatedEntriesSet,
-        cx: &AppContext,
+        cx: &App,
     ) -> Backlogged {
         log::info!("Scanning for updated entries that might need summarization...");
         let (tx, rx) = channel::bounded(512);
@@ -418,7 +418,7 @@ impl SummaryIndex {
         &self,
         paths: channel::Receiver<Vec<(Arc<Path>, Option<MTime>)>>,
         worktree_abs_path: Arc<Path>,
-        cx: &AppContext,
+        cx: &App,
     ) -> MightNeedSummaryFiles {
         let fs = self.fs.clone();
         let (rx, tx) = channel::bounded(2048);
@@ -487,7 +487,7 @@ impl SummaryIndex {
     fn summarize_files(
         &self,
         unsummarized_files: channel::Receiver<UnsummarizedFile>,
-        cx: &AppContext,
+        cx: &App,
     ) -> SummarizeFiles {
         let (summarized_tx, summarized_rx) = channel::bounded(512);
         let task = cx.spawn(|cx| async move {
@@ -528,11 +528,7 @@ impl SummaryIndex {
         }
     }
 
-    fn summarize_code(
-        code: &str,
-        path: &Path,
-        cx: &AppContext,
-    ) -> impl Future<Output = Result<String>> {
+    fn summarize_code(code: &str, path: &Path, cx: &App) -> impl Future<Output = Result<String>> {
         let start = Instant::now();
         let (summary_model_id, use_cache): (LanguageModelId, bool) = (
             "Qwen/Qwen2-7B-Instruct".to_string().into(), // TODO read this from the user's settings.
@@ -603,7 +599,7 @@ impl SummaryIndex {
     fn persist_summaries(
         &self,
         summaries: channel::Receiver<SummarizedFile>,
-        cx: &AppContext,
+        cx: &App,
     ) -> Task<Result<()>> {
         let db_connection = self.db_connection.clone();
         let digest_db = self.file_digest_db;
@@ -643,7 +639,7 @@ impl SummaryIndex {
     pub(crate) fn flush_backlog(
         &self,
         worktree_abs_path: Arc<Path>,
-        cx: &AppContext,
+        cx: &App,
     ) -> impl Future<Output = Result<()>> {
         let start = Instant::now();
         let backlogged = {