Restore editor state on reopen (#27672)

Closes https://github.com/zed-industries/zed/issues/11626
Part of https://github.com/zed-industries/zed/issues/12853

`"restore_on_file_reopen": true` in workspace settings can now be used
to enable and disable editor data between file reopens in the same pane:


https://github.com/user-attachments/assets/8d938ee1-d854-42a8-bbc3-2a4e4d7d5933

The settings are generic and panes' data store can be extended for
further entities, beyond editors.

---------------
Impl details: 

Currently, the project entry IDs seem to be stable across file reopens,
unlike BufferIds, so those were used.
Originally, the DB data was considered over in-memory one as editors
serialize their state anyway, but managing and exposing PaneIds out of
the DB is quite tedious and joining the DB data otherwise is not
possible.


Release Notes:

- Started to restore editor state on reopen

crates/workspace/src/workspace.rs

@@ -457,7 +457,8 @@ type ProjectItemOpener = fn(
 )
     -> Option<Task<Result<(Option<ProjectEntryId>, WorkspaceItemBuilder)>>>;
 
-type WorkspaceItemBuilder = Box<dyn FnOnce(&mut Window, &mut Context<Pane>) -> Box<dyn ItemHandle>>;
+type WorkspaceItemBuilder =
+    Box<dyn FnOnce(&mut Pane, &mut Window, &mut Context<Pane>) -> Box<dyn ItemHandle>>;
 
 impl Global for ProjectItemOpeners {}
 
@@ -473,10 +474,13 @@ pub fn register_project_item<I: ProjectItem>(cx: &mut App) {
             let project_item = project_item.await?;
             let project_entry_id: Option<ProjectEntryId> =
                 project_item.read_with(cx, project::ProjectItem::entry_id)?;
-            let build_workspace_item = Box::new(|window: &mut Window, cx: &mut Context<Pane>| {
-                Box::new(cx.new(|cx| I::for_project_item(project, project_item, window, cx)))
-                    as Box<dyn ItemHandle>
-            }) as Box<_>;
+            let build_workspace_item = Box::new(
+                |pane: &mut Pane, window: &mut Window, cx: &mut Context<Pane>| {
+                    Box::new(
+                        cx.new(|cx| I::for_project_item(project, pane, project_item, window, cx)),
+                    ) as Box<dyn ItemHandle>
+                },
+            ) as Box<_>;
             Ok((project_entry_id, build_workspace_item))
         }))
     });
@@ -3060,8 +3064,9 @@ impl Workspace {
             return item;
         }
 
-        let item =
-            cx.new(|cx| T::for_project_item(self.project().clone(), project_item, window, cx));
+        let item = pane.update(cx, |pane, cx| {
+            cx.new(|cx| T::for_project_item(self.project().clone(), pane, project_item, window, cx))
+        });
         let item_id = item.item_id();
         let mut destination_index = None;
         pane.update(cx, |pane, cx| {
@@ -8720,6 +8725,7 @@ mod tests {
 
             fn for_project_item(
                 _project: Entity<Project>,
+                _pane: &Pane,
                 _item: Entity<Self::Item>,
                 _: &mut Window,
                 cx: &mut Context<Self>,
@@ -8791,6 +8797,7 @@ mod tests {
 
             fn for_project_item(
                 _project: Entity<Project>,
+                _pane: &Pane,
                 _item: Entity<Self::Item>,
                 _: &mut Window,
                 cx: &mut Context<Self>,
@@ -8834,6 +8841,7 @@ mod tests {
 
             fn for_project_item(
                 _project: Entity<Project>,
+                _pane: &Pane,
                 _item: Entity<Self::Item>,
                 _: &mut Window,
                 cx: &mut Context<Self>,