debugger: Start on tabless design (#27837)

![image](https://github.com/user-attachments/assets/1cd54b70-5457-4c64-95bd-45a7055ea165)

Release Notes:

- N/A

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Anthony <anthony@zed.dev>

crates/debugger_ui/src/debugger_ui.rs

@@ -1,20 +1,38 @@
 use dap::debugger_settings::DebuggerSettings;
 use debugger_panel::{DebugPanel, ToggleFocus};
 use feature_flags::{Debugger, FeatureFlagViewExt};
-use gpui::App;
+use gpui::{App, actions};
+use new_session_modal::NewSessionModal;
 use session::DebugSession;
 use settings::Settings;
-use workspace::{
-    Pause, Restart, ShutdownDebugAdapters, StepBack, StepInto, StepOver, Stop,
-    ToggleIgnoreBreakpoints, Workspace,
-};
+use workspace::{ShutdownDebugAdapters, Workspace};
 
 pub mod attach_modal;
 pub mod debugger_panel;
-pub mod session;
+mod new_session_modal;
+pub(crate) mod session;
 
 #[cfg(test)]
-mod tests;
+pub mod tests;
+
+actions!(
+    debugger,
+    [
+        Start,
+        Continue,
+        Disconnect,
+        Pause,
+        Restart,
+        StepInto,
+        StepOver,
+        StepOut,
+        StepBack,
+        Stop,
+        ToggleIgnoreBreakpoints,
+        ClearAllBreakpoints,
+        CreateDebuggingSession,
+    ]
+);
 
 pub fn init(cx: &mut App) {
     DebuggerSettings::register(cx);
@@ -115,6 +133,23 @@ pub fn init(cx: &mut App) {
                             })
                         })
                     },
+                )
+                .register_action(
+                    |workspace: &mut Workspace, _: &CreateDebuggingSession, window, cx| {
+                        let debug_panel = workspace.panel::<DebugPanel>(cx).unwrap();
+                        let weak_panel = debug_panel.downgrade();
+                        let weak_workspace = cx.weak_entity();
+
+                        workspace.toggle_modal(window, cx, |window, cx| {
+                            NewSessionModal::new(
+                                debug_panel.read(cx).past_debug_definition.clone(),
+                                weak_panel,
+                                weak_workspace,
+                                window,
+                                cx,
+                            )
+                        });
+                    },
                 );
         })
     })