Document seasonal palettes and 4seasons branch

- Add season ranges and selection modes

README.md

@@ -151,6 +151,24 @@ bash dotfiles/install/install-macos-user.sh
 
 ---
 
+## 🌱 Seasonal palettes (4seasons branch)
+
+The `4seasons` branch adds seasonal palettes with an optional static or dynamic mode.
+
+Season ranges (Europe/Oslo):
+
+- Spring: March–May
+- Summer: June–August
+- Autumn: September–mid November
+- Winter: mid November–February
+
+When installing PS1 you can choose:
+
+- Dynamic (auto by date)
+- Static (pick a single season)
+
+---
+
 ## 🧠 Features
 
 - **Clean, modern powerline-style prompt**