Reworks how the extension communicates with the tabctl command-line tool for reliability, and adds a version handshake so the two stay in sync.

• If the tabctl command-line package is older than the extension, the extension shows an out-of-date indicator (a badge on its toolbar icon).
• Cleaner internal tab identifiers and more robust tab data.
• Groundwork for future features.

Requires the tabctl 2.0.0 command-line package. Please update BOTH the extension and the command-line tool to 2.0.0 together

More reliable tab commands and clearer error reporting: operations no longer hang on failure, stale-tab actions report errors instead of failing silently, and opening multiple URLs no longer aborts on a single bad URL.

Window focus on tab activation: When activating a tab via tabctl activate, the browser window is now focused automatically, bringing it to the foreground across virtual desktops