fix(browser): improve error handling and code quality

- Fix response.json() called before checking response.ok in popup.js
- Consolidate duplicate onInstalled listeners in background.js
- Remove unnecessary return true from content.js message handler
- Add better error handling for non-JSON responses
- Improve user experience by not auto-opening popup on install

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

browser-extension/scripts/content.js

@@ -12,9 +12,7 @@ chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
             title: document.title
         };
         sendResponse(pageInfo);
-        return true; // Indicates response will be sent asynchronously
     }
-    return false; // No async response
 });
 
 // Detect if current page is a direct file link