feat: initial Zynq XC7Z100 Flasher GUI project

Add cross-platform GUI application for programming Zynq devices
with step-by-step workflow:

- CustomTkinter GUI with dark/light theme support
- 4-step workflow: Check Env → Flash → Bootloader → Main Program
- YAML configuration with relative path resolution
- Serial monitoring and boot log parsing
- TFTP upload with CRC32 verification
- SSH/serial reboot management
- Vivado/Impact tool auto-detection

Project structure:
- app.py: Entry point
- src/: Core modules (config, flash, bitstream, tftp, serial, gui)
- config/: Default configuration template
- .flasher_env/: Python virtual environment

src/ip_verifier.py

@@ -0,0 +1,107 @@
+"""IP connectivity verification for Zynq Flasher GUI.
+
+Pings the Zynq device IP to verify network connectivity.
+"""
+
+from __future__ import annotations
+
+import platform
+import subprocess
+
+
+def ping_ip(
+    ip_address: str,
+    count: int = 3,
+    timeout: int = 5,
+) -> bool:
+    """Ping an IP address to verify connectivity.
+
+    Uses platform-appropriate ping command:
+    - Linux/macOS: ping -c <count> -W <timeout>
+    - Windows: ping -n <count> -w <timeout>
+
+    Args:
+        ip_address: IP address to ping (e.g., '192.168.100.11').
+        count: Number of ping packets to send.
+        timeout: Timeout in seconds (Linux) or milliseconds (Windows).
+
+    Returns:
+        True if all ping packets were received, False otherwise.
+    """
+    system = platform.system().lower()
+
+    if system == "windows":
+        cmd = ["ping", "-n", str(count), "-w", str(timeout * 1000), ip_address]
+    else:
+        cmd = ["ping", "-c", str(count), "-W", str(timeout), ip_address]
+
+    try:
+        result = subprocess.run(
+            cmd,
+            capture_output=True,
+            text=True,
+            timeout=timeout * count + 10,
+        )
+        return result.returncode == 0
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return False
+
+
+def ping_ip_verbose(
+    ip_address: str,
+    count: int = 3,
+    timeout: int = 5,
+) -> dict:
+    """Ping an IP address and return detailed results.
+
+    Args:
+        ip_address: IP address to ping.
+        count: Number of ping packets.
+        timeout: Timeout per packet.
+
+    Returns:
+        Dictionary with 'success' (bool), 'output' (str), and 'errors' (list).
+    """
+    system = platform.system().lower()
+
+    if system == "windows":
+        cmd = ["ping", "-n", str(count), "-w", str(timeout * 1000), ip_address]
+    else:
+        cmd = ["ping", "-c", str(count), "-W", str(timeout), ip_address]
+
+    output = ""
+    errors: list[str] = []
+
+    try:
+        result = subprocess.run(
+            cmd,
+            capture_output=True,
+            text=True,
+            timeout=timeout * count + 10,
+        )
+        output = result.stdout.strip()
+        if result.stderr:
+            errors.append(result.stderr.strip())
+        return {
+            "success": result.returncode == 0,
+            "output": output,
+            "errors": errors,
+        }
+    except subprocess.TimeoutExpired as e:
+        return {
+            "success": False,
+            "output": e.stdout if e.stdout else "",
+            "errors": ["Ping timed out"],
+        }
+    except FileNotFoundError as e:
+        return {
+            "success": False,
+            "output": "",
+            "errors": [f"ping command not found: {e}"],
+        }
+    except OSError as e:
+        return {
+            "success": False,
+            "output": "",
+            "errors": [f"OS error: {e}"],
+        }