Fix workspace creation API route to use versioned endpoint

The create-workspace-for-tab handler was calling /api/workspaces directly,
bypassing the SDK which correctly prefixes routes with /api/v1/. This caused
a "route could not be found" error when creating workspaces.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: CraftLogan

packages/chrome-extension/src/background/index.ts

@@ -670,7 +670,7 @@ chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
         if (serverId) body.server_id = serverId;
         if (url) body.preview_url = url;
 
-        const res = await fetch(`${BACKEND_URL}/api/workspaces`, {
+        const res = await fetch(`${BACKEND_URL}/api/v1/workspaces`, {
           method: "POST",
           headers: {
             Authorization: `Bearer ${apiToken}`,