feat: add installer script and builder tools

- Added install.sh for easy setup and teardown
- Added build.sh and build.bat to dynamically assemble install.sh
- Updated README.md with new installation instructions
- Fixed bidirectional WG_POLICY FORWARD rule routing in wg-policy-engine.sh

README.md

@@ -15,22 +15,30 @@ Rather than allowing all VPN clients to reach any part of your internal network,
 
 ---
 
-## 📁 File Locations & Installation
+## 📁 Installation
 
-All scripts must be placed in `/usr/local/bin/` and made executable. 
+The easiest way to install is using the provided `install.sh` script, which automatically installs dependencies, copies all scripts to `/usr/local/bin/`, sets up the systemd daemon, and enables the service.
 
-| File | Location | Description |
-|------|----------|-------------|
-| `wg-policy-lib.sh` | `/usr/local/bin/wg-policy-lib.sh` | Shared library and core validation tools. |
-| `wg-sync-policy.sh` | `/usr/local/bin/wg-sync-policy.sh` | Extracts config into atomic JSON format. |
-| `wg-policy-engine.sh` | `/usr/local/bin/wg-policy-engine.sh` | Translates JSON into iptables & ipset logic. |
-| `wg-policy-cleanup.sh` | `/usr/local/bin/wg-policy-cleanup.sh` | Reverts and cleans up all firewall traces safely. |
-| `wg-sync-watch.sh` | `/usr/local/bin/wg-sync-watch.sh` | Debounced file watcher (daemon). |
-| `wg-policy-ctl` | `/usr/local/bin/wg-policy-ctl` | Handy command-line interface tool. |
-
-Make sure they are executable:
 ```bash
-chmod +x /usr/local/bin/wg-*.sh /usr/local/bin/wg-policy-ctl
+# Install everything
+sudo ./install.sh install
+
+# Uninstall everything
+sudo ./install.sh uninstall
+```
+
+### Building the Installer (For Developers)
+
+If you modify any of the source `.sh` or `.service` files, you must rebuild the `install.sh` script using the provided builders.
+
+**On Linux (Bash):**
+```bash
+./build.sh
+```
+
+**On Windows (CMD/PowerShell):**
+```cmd
+build.bat
 ```
 
 ---
@@ -132,9 +140,9 @@ wg-policy-ctl validate
 
 ## 🔧 Systemd Integration (Watcher Daemon)
 
-If you are using the daemon mode to auto-sync changes instantly upon editing `wg0.conf` (without needing to run `wg-policy-ctl reload` or restarting the interface).
+If you use the `install.sh` script, the daemon is automatically installed, enabled, and started for you. It monitors `wg0.conf` for changes and triggers the pipeline seamlessly.
 
-### 1. File Installation
+### Manual File Installation (If not using install.sh)
 Place the three provided systemd unit files into `/etc/systemd/system/`.
 
 | Systemd File | Location | Description |