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/pane.rs

@@ -1,7 +1,8 @@
 use crate::{
     item::{
         ActivateOnClose, ClosePosition, Item, ItemHandle, ItemSettings, PreviewTabsSettings,
-        ShowCloseButton, ShowDiagnostics, TabContentParams, TabTooltipContent, WeakItemHandle,
+        ProjectItemKind, ShowCloseButton, ShowDiagnostics, TabContentParams, TabTooltipContent,
+        WeakItemHandle,
     },
     move_item,
     notifications::NotifyResultExt,
@@ -9,6 +10,7 @@ use crate::{
     workspace_settings::{AutosaveSetting, TabBarSettings, WorkspaceSettings},
     CloseWindow, NewFile, NewTerminal, OpenInTerminal, OpenOptions, OpenTerminal, OpenVisible,
     SplitDirection, ToggleFileFinder, ToggleProjectSymbols, ToggleZoom, Workspace,
+    WorkspaceItemBuilder,
 };
 use anyhow::Result;
 use collections::{BTreeSet, HashMap, HashSet, VecDeque};
@@ -321,6 +323,8 @@ pub struct Pane {
     pinned_tab_count: usize,
     diagnostics: HashMap<ProjectPath, DiagnosticSeverity>,
     zoom_out_on_close: bool,
+    /// If a certain project item wants to get recreated with specific data, it can persist its data before the recreation here.
+    pub project_item_restoration_data: HashMap<ProjectItemKind, Box<dyn Any + Send>>,
 }
 
 pub struct ActivationHistoryEntry {
@@ -526,6 +530,7 @@ impl Pane {
             pinned_tab_count: 0,
             diagnostics: Default::default(),
             zoom_out_on_close: true,
+            project_item_restoration_data: HashMap::default(),
         }
     }
 
@@ -859,7 +864,7 @@ impl Pane {
         suggested_position: Option<usize>,
         window: &mut Window,
         cx: &mut Context<Self>,
-        build_item: impl FnOnce(&mut Window, &mut Context<Pane>) -> Box<dyn ItemHandle>,
+        build_item: WorkspaceItemBuilder,
     ) -> Box<dyn ItemHandle> {
         let mut existing_item = None;
         if let Some(project_entry_id) = project_entry_id {
@@ -896,7 +901,7 @@ impl Pane {
                 suggested_position
             };
 
-            let new_item = build_item(window, cx);
+            let new_item = build_item(self, window, cx);
 
             if allow_preview {
                 self.set_preview_item_id(Some(new_item.item_id()), cx);