docs: document direct switch IME and custom layouts in README and FEATURES.md

Author: LeanBitLab

README.md

@@ -32,6 +32,8 @@
 - **🚫 Blocked Words Blacklist** - Prevent unwanted words from being suggested, with custom regex pattern support and a blacklist management screen.
 - **✉️ Auto-Read OTP** - Automatically reads OTP codes from SMS notifications for quick and easy suggestion strip entry.
 - **💾 Selective Backup & Restore** - Backup and restore settings, dictionaries, and AI prompt configurations selectively.
+- **[⌨️ Direct Switch IME](docs/FEATURES.md#10-direct-switch-target-ime)** - Map custom keycode (`-10076`) to any toolbar key to switch directly to another input method.
+- **[🎨 Custom Layouts](docs/FEATURES.md#11-custom-layouts-customization)** - Save up to five custom layout profiles with persistent slot index tracking.
 - **🔒 Privacy Choices** - Choose **Standard** (Opt-in AI, Handwriting), **Offline** (Hard-disabled network, offline GGUF model load), or **Offline Lite** (Minimalist, no AI) versions.
 - **🎨 Modern UI** - "Squircle" key backgrounds, refined icons, and polished aesthetics.
 - **🕵️ Clear Incognito Mode** - Distinct "Hat & Glasses" icon for clear visibility.

docs/FEATURES.md

@@ -17,6 +17,8 @@ LeanType integrates with AI providers to offer advanced proofreading and transla
 | 🖱️ **[Touchpad Mode](#7-touchpad-mode)** | Full-screen touchpad gestures and controls. |
 | ✍️ **[Handwriting Input](#8-handwriting-input)** | Use handwriting recognition to draw letters directly on a canvas. |
 | 👆 **[Built-in Gesture Typing](#9-built-in-gesture-typing)** | Use gesture typing without downloading native libraries. |
+| ⌨️ **[Direct Switch Target IME](#10-direct-switch-target-ime)** | Switch directly to another input method using custom keycode `-10076`. |
+| 🎨 **[Custom Layouts Customization](#11-custom-layouts-customization)** | Persistent custom layout profiles and management. |
 
 ## Summary of New Features
 
@@ -42,6 +44,8 @@ LeanType integrates with AI providers to offer advanced proofreading and transla
 | **Text Expander** | Expand custom shortcuts using dynamic template variables (date, time, clipboard, custom placeholders). | `Text correction > Text Expander` |
 | **Handwriting Input** | Draw letters or words directly on the screen keyboard space to type (standard variant, requires plugin). | `Libraries > Handwriting Input Plugin` |
 | **Built-in Gesture Typing** | Gesture typing works out of the box using our new built-in pure-Java fallback engine, removing the strict dependency on native Google libraries. | `Gesture typing` |
+| **Direct Switch Target IME** | Direct input method switching using custom keycode `-10076` assigned to toolbar keys. | `Preferences > Direct Switch Target IME` |
+| **Custom Layouts** | Supports up to 5 custom layouts with persistent layout index tracking. | `Languages > Custom layouts` |
 
 ---
 
@@ -388,4 +392,29 @@ LeanType integrates a handwriting recognition canvas that allows you to write ch
     2. Toggle **Use fallback gesture engine** to select between the pure-Java engine and the native library.
     3. Self-learning can be toggled via **Enable gesture self-learning**.
 
+---
+
+## 10. Direct Switch Target IME
+
+*   **Functionality**: Switch directly to another configured input method (and subtype) instead of opening the system input method picker.
+*   **Behavior**:
+    *   Map the custom keycode `-10076` (`SWITCH_TO_USER_IME`) to any toolbar key (supports click or long-press).
+    *   Tapping/long-pressing the key immediately switches input methods.
+*   **How to Setup**:
+    1. Go to **Settings > Preferences**.
+    2. Tap **Direct Switch Target IME** and select the target keyboard/subtype from the list of enabled inputs.
+    3. Go to **Settings > Toolbar > Customize toolbar key codes** to map `-10076` to a toolbar key.
+
+---
+
+## 11. Custom Layouts Customization
+
+*   **Functionality**: Save up to five custom layout profiles with persistent active slot tracking.
+*   **Behavior**:
+    *   The active custom layout slot index is preserved across orientation changes and switching between alphabet and symbol states.
+    *   Unused custom layout profiles can be directly deleted from settings.
+*   **How to Setup**:
+    1. Go to **Settings > Languages > Custom layouts**.
+    2. Manage custom layouts and slots as needed.
+