Prevent false positives when another window title contains 'Obsidian'.
The helper script matches with a case-insensitive regex against class+title,
so anchoring to '^obsidian$' ensures we only target the Obsidian window class.
Before: SUPER+O could focus a YouTube webapp/FreeTube titled 'Obsidian is great!'.
After: SUPER+O focuses Obsidian or launches it if not running.