Add the ability for tasks to target the center pane (#22004)

Closes #20060
Closes #20720
Closes #19873
Closes #9445

Release Notes:

- Fixed a bug where tasks would be spawned with their working directory
set to a file in some cases
- Added the ability to spawn tasks in the center pane, when spawning
from a keybinding:

```json5
[
  {
    // Assuming you have a task labeled "echo hello"
    "ctrl--": [
      "task::Spawn",
      { "task_name": "echo hello", "target": "center" }
    ]
  }
]
```

crates/task/src/lib.rs

@@ -18,11 +18,11 @@ pub use vscode_format::VsCodeTaskFile;
 
 /// Task identifier, unique within the application.
 /// Based on it, task reruns and terminal tabs are managed.
-#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Deserialize, Serialize)]
 pub struct TaskId(pub String);
 
 /// Contains all information needed by Zed to spawn a new terminal tab for the given task.
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct SpawnInTerminal {
     /// Id of the task to use when determining task tab affinity.
     pub id: TaskId,
@@ -57,6 +57,15 @@ pub struct SpawnInTerminal {
     pub show_command: bool,
 }
 
+/// An action for spawning a specific task
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct NewCenterTask {
+    /// The specification of the task to spawn.
+    pub action: SpawnInTerminal,
+}
+
+gpui::impl_actions!(tasks, [NewCenterTask]);
+
 /// A final form of the [`TaskTemplate`], that got resolved with a particualar [`TaskContext`] and now is ready to spawn the actual task.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct ResolvedTask {
@@ -75,6 +84,9 @@ pub struct ResolvedTask {
     /// Further actions that need to take place after the resolved task is spawned,
     /// with all task variables resolved.
     pub resolved: Option<SpawnInTerminal>,
+
+    /// where to sawn the task in the UI, either in the terminal panel or in the center pane
+    pub target: zed_actions::TaskSpawnTarget,
 }
 
 impl ResolvedTask {