Show multi-root workspace warning as progress instead (#2879)

### Motivation

We noticed that the warning for multi-root workspaces is sometimes ignored by users. The problem is that if you don't click anything, the LSP will never start because the promise is never resolved.

Let's show the warning under a timer and auto-dismiss so that the behaviour is less confusing.

### Implementation

I put the same warning inside a progress notification that auto-dismisses under 5 seconds.

vscode/src/rubyLsp.ts

@@ -175,7 +175,6 @@ export class RubyLsp {
     workspaceFolder: vscode.WorkspaceFolder,
     eager: boolean,
   ) {
-    const workspaceDir = workspaceFolder.uri.fsPath;
     const customBundleGemfile: string = vscode.workspace
       .getConfiguration("rubyLsp")
       .get("bundleGemfile")!;
@@ -191,31 +190,8 @@ export class RubyLsp {
     // If no lockfile exists and we're activating lazily (if the user opened a Ruby file inside a workspace we hadn't
     // activated before), then we start the language server, but we warn the user that they may be missing multi-root
     // workspace configuration
-    if (
-      customBundleGemfile.length === 0 &&
-      !lockfileExists &&
-      !this.context.globalState.get("rubyLsp.disableMultirootLockfileWarning")
-    ) {
-      const answer = await vscode.window.showWarningMessage(
-        `Activating the Ruby LSP in ${workspaceDir}, but no lockfile was found. Are you using a monorepo setup?`,
-        "See the multi-root workspace docs",
-        "Don't show again",
-      );
-
-      if (answer === "See the multi-root workspace docs") {
-        await vscode.env.openExternal(
-          vscode.Uri.parse(
-            "https://github.com/Shopify/ruby-lsp/blob/main/vscode/README.md?tab=readme-ov-file#multi-root-workspaces",
-          ),
-        );
-      }
-
-      if (answer === "Don't show again") {
-        await this.context.globalState.update(
-          "rubyLsp.disableMultirootLockfileWarning",
-          true,
-        );
-      }
+    if (customBundleGemfile.length === 0 && !lockfileExists) {
+      await this.showStandaloneWarning(workspaceFolder.uri.fsPath);
     }
 
     const workspace = new Workspace(
@@ -797,4 +773,44 @@ export class RubyLsp {
 
     return false;
   }
+
+  private async showStandaloneWarning(workspaceDir: string) {
+    await vscode.window.withProgress(
+      {
+        location: vscode.ProgressLocation.Notification,
+        title: "No bundle found. Launching in standalone mode in 5 seconds",
+        cancellable: true,
+      },
+      async (progress, token) => {
+        progress.report({
+          message:
+            "If working in a monorepo, cancel to see configuration instructions",
+        });
+
+        await new Promise<void>((resolve) => {
+          token.onCancellationRequested(() => {
+            resolve();
+          });
+
+          setTimeout(resolve, 5000);
+        });
+
+        if (token.isCancellationRequested) {
+          const answer = await vscode.window.showWarningMessage(
+            `Could not find a lockfile in ${workspaceDir}. Are you using a monorepo setup?`,
+            "See the multi-root workspace docs",
+            "Launch anyway",
+          );
+
+          if (answer === "See the multi-root workspace docs") {
+            const uri = vscode.Uri.parse(
+              "https://github.com/Shopify/ruby-lsp/blob/main/vscode/README.md?tab=readme-ov-file#multi-root-workspaces",
+            );
+
+            await vscode.env.openExternal(uri);
+          }
+        }
+      },
+    );
+  }
 }