feat: add tip about toggling project panel focus with cmd-shift-e

tips/toggle-project-panel-focus.mdx

@@ -0,0 +1,52 @@
+---
+title: Toggle Project Panel Focus with Cmd-Shift-E
+subtitle: Open or focus the file tree sidebar with a single keyboard shortcut
+category: shortcuts
+difficulty: beginner
+tags:
+  - panels
+  - keybindings
+  - navigation
+  - workflow
+---
+
+Press **`Cmd-Shift-E`** (macOS) or **`Ctrl-Shift-E`** (Linux/Windows) to open the Project Panel or shift focus to it when it's already visible.
+
+## How to Use
+
+1. Press **`Cmd-Shift-E`** to show the Project Panel
+2. Press it again to return focus to the editor (if the panel is already open)
+
+This is a **toggle focus** action, meaning it both reveals the panel and moves your cursor there, ready for keyboard navigation.
+
+## What You Can Do in the Project Panel
+
+Once focused, use the keyboard to manage your project without touching the mouse:
+
+- **Arrow keys** — Navigate up and down through files and folders
+- **`Right`** — Expand a directory
+- **`Left`** — Collapse a directory
+- **`Space`** — Preview a file without creating a permanent tab
+- **`Cmd-N`** — Create a new file in the selected directory
+- **`Alt-Cmd-N`** — Create a new directory
+- **`F2`** — Rename the selected entry
+- **`Cmd-Backspace`** — Move selected entries to trash
+
+## Why This Matters
+
+**Instant access**: Jump to the file tree without reaching for the mouse.
+
+**Keyboard-first workflow**: Create, rename, and delete files entirely from the keyboard.
+
+**Context switching**: Quickly check file structure or git status, then return to editing with the same shortcut.
+
+## Related Shortcuts
+
+| Action | macOS | Linux/Windows |
+|--------|-------|---------------|
+| Toggle Outline Panel | `Cmd-Shift-B` | `Ctrl-Shift-B` |
+| Toggle Terminal Panel | `Ctrl-`` ` | `Ctrl-`` ` |
+| Toggle Agent Panel | `Cmd-?` | `Ctrl-?` |
+| Open File Finder | `Cmd-P` | `Ctrl-P` |
+
+Mastering **`Cmd-Shift-E`** keeps your hands on the keyboard and your workflow uninterrupted.