Add documentation for keyboard shortcuts

src/SUMMARY.md

@@ -12,6 +12,7 @@
 - [Fediverse Interaction](users/06-fediverse-interaction.md)
 - [Other Features](users/07-other-features.md)
 - [History of Lemmy](users/08-history-of-lemmy.md)
+- [Keyboard Shortcuts](users/09-keyboard-shortcuts.md)
 
 # For Admins
 

src/users/09-keyboard-shortcuts.md

@@ -0,0 +1,82 @@
+# Keyboard Shortcuts
+
+Lemmy-UI supports keyboard shortcuts for navigation and interaction with posts and comments.
+
+## Availability
+
+Keyboard shortcuts work on pages that display posts or comments:
+- Home page and community pages
+- Individual post pages
+- User profiles
+- Search results
+- Saved posts and comments
+- Inbox and mentions
+- Moderation queues
+
+Shortcuts are automatically disabled when typing in input fields or forms.
+
+## Navigation
+
+### Post Lists
+
+Navigate between posts on listing pages.
+
+| Key | Action |
+|-----|--------|
+| **j** | Next post |
+| **k** | Previous post |
+| **J** | Last post |
+| **K** | First post |
+
+The currently selected post is highlighted. You can also click on a post to select it.
+
+### Comments
+
+Navigate through comments when viewing a post.
+
+| Key | Action |
+|-----|--------|
+| **j** | Next comment (depth-first) |
+| **k** | Previous comment |
+| **J** | Next sibling (same level) |
+| **K** | Previous sibling (same level) |
+| **p** | Parent comment |
+| **t** | Thread root (top-level comment) |
+
+## Actions
+
+Perform actions on the highlighted post or comment.
+
+| Key | Action | Requires Login |
+|-----|--------|----------------|
+| **a** | Upvote (toggle) | Yes |
+| **z** | Downvote (toggle) | Yes |
+| **s** | Save/unsave (toggle) | Yes |
+| **x** | Expand post | No |
+| **e** | Edit | Yes (own content only) |
+| **r** | Reply (comments) / Go to community (posts) | Context-dependent |
+| **.** | Open actions menu | No |
+| **Enter** | Collapse/expand comment | No |
+
+**Notes:**
+- Voting and save keys toggle - press again to undo
+- The `r` key opens the community page when viewing posts, and replies to the comment when viewing comments
+- The actions menu (`.`) provides access to additional options like report, block, and moderation actions
+
+## Links
+
+Open posts, comments, profiles, and communities. Lowercase keys open in the current tab, uppercase (Shift) opens in a new tab.
+
+| Key | Action |
+|-----|--------|
+| **c** / **C** | Open comments |
+| **l** / **L** | Open post link |
+| **u** / **U** | Open user profile |
+| **r** / **R** | Open community |
+
+## Important Notes
+
+- Shortcuts are disabled while typing in text inputs, textareas, or forms
+- Browser extensions like Vimium may intercept keyboard shortcuts
+- Browser-specific shortcuts always take priority
+- On mobile, shortcuts only work with external keyboards