dsh-find-bar: Adding ⌘F In-Page Find to Desktop Apps

dsh-find-bar is a plugin that provides ⌘F/Ctrl+F find functionality for the DSH desktop app. It intercepts the global keyboard shortcut, uses TreeWalker to traverse text nodes, and leverages the CSS Custom Highlight API to render highlights with React compatibility. It supports full-text search, match counting, jumping, and streaming input, but only for DOM content with a maximum of 5,000 matches. Restart the app after installation for changes to take effect.