fix(project): keep attachments in the current project (#2320)

Attach adds a trusted folder to the current project without reopening it or moving its root. Attachments live in the primary project's private .openidea/workspace.json, and detaching the last one restores a plain project.

ProjectInfo.name stays the primary project's name; displayName supplies window titles, project tabs and Recent Projects. Attach is no longer a remembered opening policy, and File > Attach Project is available when the policy is not Ask. Attached folders must be trusted, and Restricted Mode names any attached folder that blocks trust. Explicit workspaces keep their behaviour and still cannot be created in or inside a linked project.

src-tauri/src/remote_dev.rs

@@ -528,7 +528,7 @@ pub async fn remote_connect(
         peer.request("invoke", call, None).await.map_err(ide_host::rpc::error_from_reply)?;
     // As the server resolved it (symlinks, a trailing `/`): the frontend compares it with the project's.
     let root = serde_json::to_value(&project.root).ok().and_then(|v| v.as_str().map(str::to_owned)).unwrap_or(root);
-    let _ = window.set_title(&format!("{} [{title_tag}]", project.name));
+    let _ = window.set_title(&format!("{} [{title_tag}]", project.display_name));
     let connection = Arc::new(Connection {
         peer,
         target: target.clone(),