feat: add diff.yazi plugin

diff.yazi/README.md

@@ -0,0 +1,22 @@
+# diff.yazi
+
+Diff the selected file with the hovered file, create a living patch, and copy it to the clipboard.
+
+## Installation
+
+```sh
+ya pack -a yazi-rs/plugins#diff
+```
+
+## Usage
+
+Add this to your `~/.config/yazi/keymap.toml`:
+
+```toml
+[[manager.prepend_keymap]]
+on   = [ "<C-d>" ]
+run  = "plugin diff"
+desc = "Diff the selected with the hovered file"
+```
+
+Make sure the <kbd>C</kbd> + <kbd>d</kbd> key is not used elsewhere.