debugger: Allow users to include PickProcessId in debug tasks and resolve Pid (#42913)

Closes #33286

This PR adds support for Zed's `$ZED_PICK_PID` command in debug
configurations, which allows users to select a process to attach to at
debug time. When this variable is present in a debug configuration, Zed
automatically opens a process picker modal.

Follow up for this will be integrating this variable in the task system
instead of just the debug configuration system.

Release Notes:

- Added `$ZED_PICK_PID` variable for debug configurations, allowing
users to select which process to attach the debugger to at runtime

---------

Co-authored-by: Remco Smits <djsmits12@gmail.com>

crates/task/src/vscode_debug_format.rs

@@ -68,7 +68,11 @@ impl TryFrom<VsCodeDebugTaskFile> for DebugTaskFile {
                 VariableName::RelativeFile.to_string(),
             ),
             ("file".to_owned(), VariableName::File.to_string()),
-        ]));
+        ]))
+        .with_commands([(
+            "pickMyProcess".to_owned(),
+            VariableName::PickProcessId.to_string(),
+        )]);
         let templates = file
             .configurations
             .into_iter()
@@ -96,7 +100,7 @@ fn task_type_to_adapter_name(task_type: &str) -> String {
 mod tests {
     use serde_json::json;
 
-    use crate::{DebugScenario, DebugTaskFile};
+    use crate::{DebugScenario, DebugTaskFile, VariableName};
 
     use super::VsCodeDebugTaskFile;
 
@@ -152,4 +156,39 @@ mod tests {
             }])
         );
     }
+
+    #[test]
+    fn test_command_pickmyprocess_replacement() {
+        let raw = r#"
+            {
+                "version": "0.2.0",
+                "configurations": [
+                    {
+                        "name": "Attach to Process",
+                        "request": "attach",
+                        "type": "cppdbg",
+                        "processId": "${command:pickMyProcess}"
+                    }
+                ]
+            }
+        "#;
+        let parsed: VsCodeDebugTaskFile =
+            serde_json_lenient::from_str(raw).expect("deserializing launch.json");
+        let zed = DebugTaskFile::try_from(parsed).expect("converting to Zed debug templates");
+
+        let expected_placeholder = format!("${{{}}}", VariableName::PickProcessId);
+        pretty_assertions::assert_eq!(
+            zed,
+            DebugTaskFile(vec![DebugScenario {
+                label: "Attach to Process".into(),
+                adapter: "CodeLLDB".into(),
+                config: json!({
+                    "request": "attach",
+                    "processId": expected_placeholder,
+                }),
+                tcp_connection: None,
+                build: None
+            }])
+        );
+    }
 }