feat(ostp-client-linux): add CLI VPN client for Linux

New CLI client for Linux with TUN interface support:
- Interactive setup wizard with profile management
- Connect/disconnect commands with root privilege check
- Status monitoring (interface stats, traffic counters)
- Test connection (handshake verification)
- Profile management (add/remove/set-default)
- Anti-VM detection (production mode only)
- Stealth mode (TLS mimicry, geo-SNI selection)

Features:
- Static musl binary (2.0 MB) - universal Linux
- Config storage: ~/.config/ostp/profiles.json
- TUN interface: ostp0 (10.X.Y.Z)
- Security: libc::geteuid() root check, ostp-guard integration
- Error handling: graceful disconnect on Ctrl+C

Commands:
- ostp-client-linux setup             # Interactive wizard
- ostp-client-linux connect --profile default
- ostp-client-linux connect --server 1.2.3.4:443 --psk HEX
- ostp-client-linux status            # Show connection info
- ostp-client-linux disconnect        # Kill running client
- ostp-client-linux profiles list     # List saved profiles
- ostp-client-linux test --server X --psk Y

Distribution updates:
- Added ostp-client-linux (2.0 MB) to linux-x64 package
- Updated SHA256SUMS with all 3 binaries
- Updated README.md with client installation guide
- Rebuilt ostp-server-linux-x64.tar.gz (6.86 MB total)

Note: TUN interface and traffic relay are TODO (placeholders)

dist/linux-x64/README.md

@@ -1,11 +1,17 @@
 # OSTP Server - Linux x64 Distribution
 
-Universal Linux binaries (statically linked with musl) for OSTP VPN server deployment.
+Universal Linux binaries (statically linked with musl) for OSTP VPN server and client deployment.
 
 ## 📦 Contents
 
+**Server Binaries:**
 - **ostp-server** (9.2 MB) - VPN server with AEAD encryption, TLS mimicry, UDP-over-TCP
 - **oncp-master** (4.8 MB) - Control plane API server for node/user management
+
+**Client Binary:**
+- **ostp-client-linux** (2.0 MB) - CLI VPN client for Linux (TUN interface)
+
+**Supporting Files:**
 - **SHA256SUMS** - Integrity verification checksums
 - **deploy.sh** - Automated deployment script
 - **server.json.example** - ostp-server configuration template
@@ -15,13 +21,15 @@ Universal Linux binaries (statically linked with musl) for OSTP VPN server deplo
 
 ## 🚀 Quick Start
 
-### 1. Verify Integrity
+### Server Installation
+
+#### 1. Verify Integrity
 
 ```bash
 sha256sum -c SHA256SUMS
 ```
 
-### 2. Deploy with Script (Recommended)
+#### 2. Deploy with Script (Recommended)
 
 ```bash
 chmod +x deploy.sh
@@ -35,6 +43,49 @@ The script will:
 - Set up firewall rules
 - Start services
 
+### Client Installation
+
+#### 1. Install Client Binary
+
+```bash
+chmod +x ostp-client-linux
+sudo cp ostp-client-linux /usr/local/bin/
+```
+
+#### 2. Setup Profile
+
+```bash
+ostp-client-linux setup
+```
+
+Interactive wizard will prompt for:
+- Server address (e.g., `vpn.example.com:443`)
+- Pre-shared key (64 hex characters)
+- Country code for SNI mimicry (US, RU, DE, etc.)
+- Profile name (e.g., "US-West")
+
+#### 3. Connect to VPN
+
+```bash
+# Using saved profile
+sudo ostp-client-linux connect --profile default
+
+# Or with explicit parameters
+sudo ostp-client-linux connect --server 1.2.3.4:443 --psk YOUR_PSK --country US
+```
+
+#### 4. Check Status
+
+```bash
+ostp-client-linux status
+```
+
+#### 5. Disconnect
+
+```bash
+sudo ostp-client-linux disconnect
+```
+
 ### 3. Manual Installation
 
 ```bash

dist/linux-x64/SHA256SUMS

@@ -1,2 +1,3 @@
-53de7690ddcd22828d1d2c55bec75e7a43aa6476827d8162615549b08a1a39dc  oncp-master
+cf3996eac77ed62d184452b3032e3bffc60c120e77cee57899a33893322b0cc4  ostp-client-linux
 d3ec5b5ee8c90f1f92667458f44a795159157ae64e8d5073888838fbfce286e2  ostp-server
+53de7690ddcd22828d1d2c55bec75e7a43aa6476827d8162615549b08a1a39dc  oncp-master