Debugger implementation (#13433)

###  DISCLAIMER

> As of 6th March 2025, debugger is still in development. We plan to
merge it behind a staff-only feature flag for staff use only, followed
by non-public release and then finally a public one (akin to how Git
panel release was handled). This is done to ensure the best experience
when it gets released.

### END OF DISCLAIMER 

**The current state of the debugger implementation:**


https://github.com/user-attachments/assets/c4deff07-80dd-4dc6-ad2e-0c252a478fe9


https://github.com/user-attachments/assets/e1ed2345-b750-4bb6-9c97-50961b76904f

----

All the todo's are in the following channel, so it's easier to work on
this together:
https://zed.dev/channel/zed-debugger-11370

If you are on Linux, you can use the following command to join the
channel:
```cli
zed https://zed.dev/channel/zed-debugger-11370 
```

## Current Features

- Collab
  - Breakpoints
    - Sync when you (re)join a project
    - Sync when you add/remove a breakpoint
  - Sync active debug line
  - Stack frames
    - Click on stack frame
      - View variables that belong to the stack frame
      - Visit the source file
    - Restart stack frame (if adapter supports this)
  - Variables
  - Loaded sources
  - Modules
  - Controls
    - Continue
    - Step back
      - Stepping granularity (configurable)
    - Step into
      - Stepping granularity (configurable)
    - Step over
      - Stepping granularity (configurable)
    - Step out
      - Stepping granularity (configurable)
  - Debug console
- Breakpoints
  - Log breakpoints
  - line breakpoints
  - Persistent between zed sessions (configurable)
  - Multi buffer support
  - Toggle disable/enable all breakpoints
- Stack frames
  - Click on stack frame
    - View variables that belong to the stack frame
    - Visit the source file
    - Show collapsed stack frames
  - Restart stack frame (if adapter supports this)
- Loaded sources
  - View all used loaded sources if supported by adapter.
- Modules
  - View all used modules (if adapter supports this)
- Variables
  - Copy value
  - Copy name
  - Copy memory reference
  - Set value (if adapter supports this)
  - keyboard navigation
- Debug Console
  - See logs
  - View output that was sent from debug adapter
    - Output grouping
  - Evaluate code
    - Updates the variable list
    - Auto completion
- If not supported by adapter, we will show auto-completion for existing
variables
- Debug Terminal
- Run custom commands and change env values right inside your Zed
terminal
- Attach to process (if adapter supports this)
  - Process picker
- Controls
  - Continue
  - Step back
    - Stepping granularity (configurable)
  - Step into
    - Stepping granularity (configurable)
  - Step over
    - Stepping granularity (configurable)
  - Step out
    - Stepping granularity (configurable)
  - Disconnect
  - Restart
  - Stop
- Warning when a debug session exited without hitting any breakpoint
- Debug view to see Adapter/RPC log messages
- Testing
  - Fake debug adapter
    - Fake requests & events

---

Release Notes:

- N/A

---------

Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>
Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Piotr Osiewicz <peterosiewicz@gmail.com>
Co-authored-by: Piotr <piotr@zed.dev>

crates/workspace/src/pane.rs

@@ -219,7 +219,7 @@ pub enum Event {
         idx: usize,
     },
     RemovedItem {
-        item_id: EntityId,
+        item: Box<dyn ItemHandle>,
     },
     Split(SplitDirection),
     JoinAll,
@@ -247,9 +247,9 @@ impl fmt::Debug for Event {
                 .finish(),
             Event::Remove { .. } => f.write_str("Remove"),
             Event::RemoveItem { idx } => f.debug_struct("RemoveItem").field("idx", idx).finish(),
-            Event::RemovedItem { item_id } => f
+            Event::RemovedItem { item } => f
                 .debug_struct("RemovedItem")
-                .field("item_id", item_id)
+                .field("item", &item.item_id())
                 .finish(),
             Event::Split(direction) => f
                 .debug_struct("Split")
@@ -315,6 +315,7 @@ pub struct Pane {
     display_nav_history_buttons: Option<bool>,
     double_click_dispatch_action: Box<dyn Action>,
     save_modals_spawned: HashSet<EntityId>,
+    close_pane_if_empty: bool,
     pub new_item_context_menu_handle: PopoverMenuHandle<ContextMenu>,
     pub split_item_context_menu_handle: PopoverMenuHandle<ContextMenu>,
     pinned_tab_count: usize,
@@ -519,6 +520,7 @@ impl Pane {
             _subscriptions: subscriptions,
             double_click_dispatch_action,
             save_modals_spawned: HashSet::default(),
+            close_pane_if_empty: true,
             split_item_context_menu_handle: Default::default(),
             new_item_context_menu_handle: Default::default(),
             pinned_tab_count: 0,
@@ -706,6 +708,11 @@ impl Pane {
         self.can_split_predicate = can_split_predicate;
     }
 
+    pub fn set_close_pane_if_empty(&mut self, close_pane_if_empty: bool, cx: &mut Context<Self>) {
+        self.close_pane_if_empty = close_pane_if_empty;
+        cx.notify();
+    }
+
     pub fn set_can_navigate(&mut self, can_navigate: bool, cx: &mut Context<Self>) {
         self.toolbar.update(cx, |toolbar, cx| {
             toolbar.set_can_navigate(can_navigate, cx);
@@ -1632,6 +1639,13 @@ impl Pane {
 
                 // Remove the item from the pane.
                 pane.update_in(&mut cx, |pane, window, cx| {
+                    pane.remove_item(
+                        item_to_close.item_id(),
+                        false,
+                        pane.close_pane_if_empty,
+                        window,
+                        cx,
+                    );
                     pane.remove_item(item_to_close.item_id(), false, true, window, cx);
                 })
                 .ok();
@@ -1739,13 +1753,9 @@ impl Pane {
             }
         }
 
-        cx.emit(Event::RemoveItem { idx: item_index });
-
         let item = self.items.remove(item_index);
 
-        cx.emit(Event::RemovedItem {
-            item_id: item.item_id(),
-        });
+        cx.emit(Event::RemovedItem { item: item.clone() });
         if self.items.is_empty() {
             item.deactivated(window, cx);
             if close_pane_if_empty {
@@ -2779,7 +2789,7 @@ impl Pane {
                                     window.dispatch_action(
                                         this.double_click_dispatch_action.boxed_clone(),
                                         cx,
-                                    )
+                                    );
                                 }
                             })),
                     ),