docs: Add dynamic splitscreen documentation (Phase 6)

README.md updates:
- New "Dynamic Splitscreen Mode (v3.0.0)" section with full feature docs
- How it works: join/leave flow explanation
- Window repositioning behavior for 1-4 players
- Optional package requirements (inotify-tools, xdotool, etc.)
- Limitations section (Wayland, Game Mode, max players)
- Added to Recent Improvements section

CLAUDE.md updates:
- Version bump to 3.0.0
- Issue #5 added: Dynamic Splitscreen implementation details
- Updated Implementation Order checklist

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: aradanmn

CLAUDE.md

@@ -6,7 +6,7 @@ This document provides essential context for AI assistants working on this codeb
 
 **Minecraft Splitscreen Steam Deck & Linux Installer** - An automated installer for setting up splitscreen Minecraft (1-4 players) on Steam Deck and Linux systems.
 
-**Version:** 2.0.0
+**Version:** 3.0.0
 **Repository:** https://github.com/aradanmn/MinecraftSplitscreenSteamdeck
 **License:** MIT
 
@@ -388,11 +388,36 @@ The installer generates `minecraftSplitscreen.sh` at runtime with:
 
 ---
 
+### Issue #5: Dynamic Splitscreen Mode (v3.0.0) ✅ IMPLEMENTED
+**Feature:** Players can join and leave mid-session without coordinating start times.
+
+**Technical Implementation:**
+- Controller monitoring via `inotifywait` with polling fallback
+- Process tracking with PID arrays for 4 instance slots
+- External window repositioning via `xdotool`/`wmctrl` on X11
+- Instance restart fallback for Game Mode (gamescope)
+- Event loop architecture in generated launcher script
+- Mode selection UI (static vs dynamic) at launch
+
+**Files modified:**
+- `modules/launcher_script_generator.sh` - Major changes (dynamic mode logic, event handlers, window repositioning)
+- `modules/version_info.sh` - Version bump to 3.0.0
+- All module headers - Version update to 3.0.0
+- `README.md` - Feature documentation
+
+**Optional dependencies for best experience:**
+- `inotify-tools` - Efficient controller hotplug detection
+- `xdotool`/`wmctrl` - Smooth window repositioning on X11
+- `libnotify` - Desktop notifications when players join/leave
+
+---
+
 ### Implementation Order
 1. ✅ **Issue #3 (Logging)** - DONE. All print_* functions auto-log.
 2. ✅ **Issue #1 (User Input)** - DONE. All modules refactored to use `prompt_user()` and `prompt_yes_no()`.
-3. ⏳ **Issue #2 (Controller Detection)** - Improves Steam Deck UX
-4. ⏳ **Issue #4 (Versioning)** - Can wait until Minecraft actually releases new format
+3. ✅ **Issue #5 (Dynamic Splitscreen)** - DONE. Players can join/leave mid-session.
+4. ⏳ **Issue #2 (Controller Detection)** - Improves Steam Deck UX
+5. ⏳ **Issue #4 (Versioning)** - Can wait until Minecraft actually releases new format
 
 ## Useful Debugging
 

README.md

@@ -18,6 +18,54 @@ This project provides an easy way to set up splitscreen Minecraft on Steam Deck
 - **Automatic Dependency Resolution:** Uses live API calls to discover and install all mod dependencies without manual maintenance
 - **Smart Cleanup:** Automatically removes temporary files and directories after successful setup
 
+## Dynamic Splitscreen Mode (v3.0.0)
+
+Version 3.0.0 introduces **Dynamic Splitscreen** - players can now join and leave mid-session without everyone needing to start at the same time.
+
+### How It Works
+
+1. **Launch the game** - Choose "Dynamic" mode when prompted (or press 2)
+2. **Start playing** - The first controller detected launches Player 1 in fullscreen
+3. **Players join** - When a new controller connects, a new Minecraft instance launches and all windows reposition automatically
+4. **Players leave** - When a player quits Minecraft, remaining windows expand to use the available space
+5. **Session ends** - When all players have exited, the launcher closes
+
+### Window Repositioning
+
+The system automatically repositions windows based on player count:
+- **1 player**: Fullscreen
+- **2 players**: Top/Bottom split
+- **3-4 players**: Quad split (2x2 grid)
+
+**Desktop Mode (X11)**: Uses `xdotool` or `wmctrl` for smooth, non-disruptive window repositioning.
+
+**Steam Deck Game Mode**: Restarts instances with new positions (the splitscreen mod only reads configuration at startup).
+
+### Requirements for Dynamic Mode
+
+For the best experience, install these optional packages:
+
+```bash
+# Debian/Ubuntu
+sudo apt install inotify-tools xdotool wmctrl libnotify-bin
+
+# Fedora
+sudo dnf install inotify-tools xdotool wmctrl libnotify
+
+# Arch
+sudo pacman -S inotify-tools xdotool wmctrl libnotify
+```
+
+- `inotify-tools`: Efficient controller hotplug detection (falls back to polling if unavailable)
+- `xdotool`/`wmctrl`: Smooth window repositioning on X11
+- `libnotify`: Desktop notifications when players join/leave
+
+### Limitations
+
+- **Wayland**: External window management may not work on pure Wayland; XWayland apps typically work
+- **Game Mode**: Window repositioning requires restarting instances (brief interruption)
+- **Maximum 4 players**: Hardware and mod limitation
+
 ## Requirements
 - Linux (Steam Deck or any modern distro)
 - Internet connection for initial setup
@@ -226,6 +274,10 @@ Select your new Minecraft version when prompted. The installer will:
 - **Figure out preconfiguring controllers within controllable (if possible)** - Investigate automatic controller assignment configuration to avoid having Controllable grab the same controllers as all the other instances, ensuring each player gets their own dedicated controller
 
 ## Recent Improvements
+- ✅ **Dynamic Splitscreen (v3.0.0)**: Players can join and leave mid-session - no need for everyone to start at the same time
+- ✅ **Controller Hotplug**: Real-time detection of controller connections/disconnections
+- ✅ **Automatic Window Repositioning**: Windows automatically resize when player count changes
+- ✅ **Desktop Notifications**: Get notified when players join or leave
 - ✅ **Auto-Generated Launcher Script**: The splitscreen launcher is now generated at install time with correct paths baked in - no more hardcoded paths
 - ✅ **Flatpak Support**: Works with both Flatpak and AppImage installations of PollyMC and PrismLauncher
 - ✅ **Smart Launcher Detection**: Automatically detects existing launcher installations and uses them instead of downloading new ones