docs: describe available features

README.md

@@ -2,15 +2,30 @@
 
 Open a local folder and explore your files inside the browser. Your files stay private and won't be uploaded anywhere.
 
-## Features
+## Scope
 
 - Explore your local files inside the browser.
 - Play web-ready audio and video files.
 - Browse and present your images.
 - Display parsed Markdown files.
-- Inspect text documents with syntax highlighting for several languages.
+- Inspect text based documents with syntax highlighting for several languages.
 - View PDF files.
+
+## Features
+
 - Install Peekaboo as PWA. It works offline too.
+- Add a `README.md` file to display its contents above the listed directory entries.
+- Filter current directory entries by search term.
+- Filter files and folders in current directory by tag. Add tags (comma separated) in square brackets at the end of the file or folder name. Examples:
+  ```
+  Wallpapers [Dark, Space]
+  Wallpapers [Abstract, Dark]
+  IMG001 [2021, Berlin].jpg
+  IMG002 [2022, New York].jpg
+  ```
+- Place an image file named like the folder to define a permanent cover/thumbnail. Example:
+  - Folder name: `Wallpapers`
+  - Image inside folder: `Wallpapers.jpg`
 
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