Unify the tasks modal and the new session modal (#31646)

Release Notes:

- Debugger Beta: added a button to the quick action bar to start a debug
session or spawn a task, depending on which of these actions was taken
most recently.
- Debugger Beta: incorporated the tasks modal into the new session modal
as an additional tab.

---------

Co-authored-by: Julia Ryan <juliaryan3.14@gmail.com>
Co-authored-by: Julia Ryan <p1n3appl3@users.noreply.github.com>
Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Mikayla <mikayla@zed.dev>

crates/zed/src/zed/quick_action_bar.rs

@@ -133,6 +133,46 @@ impl Render for QuickActionBar {
             )
         });
 
+        let last_run_debug = self
+            .workspace
+            .read_with(cx, |workspace, cx| {
+                workspace
+                    .debugger_provider()
+                    .map(|provider| provider.debug_scenario_scheduled_last(cx))
+                    .unwrap_or_default()
+            })
+            .ok()
+            .unwrap_or_default();
+
+        let run_button = if last_run_debug {
+            QuickActionBarButton::new(
+                "debug",
+                IconName::Debug, // TODO: use debug + play icon
+                false,
+                Box::new(debugger_ui::Start),
+                focus_handle.clone(),
+                "Debug",
+                move |_, window, cx| {
+                    window.dispatch_action(Box::new(debugger_ui::Start), cx);
+                },
+            )
+        } else {
+            let action = Box::new(tasks_ui::Spawn::ViaModal {
+                reveal_target: None,
+            });
+            QuickActionBarButton::new(
+                "run",
+                IconName::Play,
+                false,
+                action.boxed_clone(),
+                focus_handle.clone(),
+                "Spawn Task",
+                move |_, window, cx| {
+                    window.dispatch_action(action.boxed_clone(), cx);
+                },
+            )
+        };
+
         let assistant_button = QuickActionBarButton::new(
             "toggle inline assistant",
             IconName::ZedAssistant,
@@ -561,6 +601,7 @@ impl Render for QuickActionBar {
                 AgentSettings::get_global(cx).enabled && AgentSettings::get_global(cx).button,
                 |bar| bar.child(assistant_button),
             )
+            .child(run_button)
             .children(code_actions_dropdown)
             .children(editor_selections_dropdown)
             .child(editor_settings_dropdown)