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/reboot_manager.py

@@ -0,0 +1,213 @@
+"""Reboot manager for Zynq Flasher GUI.
+
+Handles rebooting the Zynq device via SSH or serial commands.
+"""
+
+from __future__ import annotations
+
+import importlib
+import platform
+import shutil
+import subprocess
+import time
+from dataclasses import dataclass
+from typing import Callable
+
+from config_manager import Config
+
+
+@dataclass
+class RebootResult:
+    """Result of a reboot operation."""
+
+    success: bool
+    message: str
+    method: str = ""
+    output: str = ""
+
+
+ProgressCallback = Callable[[str, str], None] | None
+
+
+def reboot_via_ssh(
+    config: Config,
+    timeout: int | None = None,
+    callback: ProgressCallback = None,
+) -> RebootResult:
+    """Reboot the Zynq device via SSH.
+
+    Sends a 'reboot' command over SSH to the Zynq device.
+
+    Args:
+        config: Application configuration.
+        timeout: Seconds to wait for reboot acknowledgment.
+        callback: Optional progress callback.
+
+    Returns:
+        RebootResult with status.
+    """
+    timeout = timeout or config.reboot_timeout
+    ip = config.zynq_ip
+
+    if callback:
+        callback("start", f"Sending reboot via SSH to {ip}...")
+
+    # Check ssh availability
+    if not shutil.which("ssh"):
+        return RebootResult(
+            success=False,
+            message="ssh command not found in PATH",
+            method="ssh",
+        )
+
+    # Try SSH reboot
+    cmd = ["ssh", "-o", "ConnectTimeout=5", "-o", "StrictHostKeyChecking=no",
+           f"root@{ip}", "reboot"]
+
+    try:
+        result = subprocess.run(
+            cmd,
+            capture_output=True,
+            text=True,
+            timeout=10,
+        )
+        if callback:
+            if result.returncode == 0:
+                callback("progress", f"Reboot command sent to {ip}")
+            else:
+                callback("error", f"SSH reboot failed: {result.stderr.strip()}")
+
+        # Wait for device to come back
+        if result.returncode == 0 and callback:
+            callback("progress", f"Waiting {timeout}s for device to reboot...")
+
+        return RebootResult(
+            success=result.returncode == 0,
+            message="Reboot command sent" if result.returncode == 0 else f"SSH reboot failed: {result.stderr.strip()}",
+            method="ssh",
+            output=result.stdout,
+        )
+    except subprocess.TimeoutExpired:
+        return RebootResult(
+            success=False,
+            message="SSH reboot timed out",
+            method="ssh",
+        )
+    except FileNotFoundError:
+        return RebootResult(
+            success=False,
+            message="ssh command not found",
+            method="ssh",
+        )
+    except OSError as e:
+        return RebootResult(
+            success=False,
+            message=f"OS error: {e}",
+            method="ssh",
+        )
+
+
+def reboot_via_serial(
+    config: Config,
+    callback: ProgressCallback = None,
+) -> RebootResult:
+    """Reboot the Zynq device via serial port.
+
+    Sends a reboot command through the serial console.
+
+    Args:
+        config: Application configuration.
+        callback: Optional progress callback.
+
+    Returns:
+        RebootResult with status.
+    """
+    if not config.serial_port:
+        return RebootResult(
+            success=False,
+            message="No serial port configured",
+            method="serial",
+        )
+
+    if callback:
+        callback("start", f"Sending reboot via serial {config.serial_port}...")
+
+    try:
+        import serial
+
+        with serial.Serial(
+            config.serial_port,
+            config.serial_baudrate,
+            timeout=5,
+        ) as ser:
+            ser.reset_input_buffer()
+            # Send Ctrl+C to break out of any running process
+            ser.write(b"\x03")
+            time.sleep(0.5)
+            # Send reboot command
+            ser.write(b"reboot\r\n")
+            ser.reset_input_buffer()
+
+        if callback:
+            callback("progress", "Reboot command sent via serial")
+
+        return RebootResult(
+            success=True,
+            message="Reboot command sent via serial",
+            method="serial",
+        )
+    except ImportError:
+        return RebootResult(
+            success=False,
+            message="pyserial not installed",
+            method="serial",
+        )
+    except serial.SerialException as e:
+        return RebootResult(
+            success=False,
+            message=f"Serial error: {e}",
+            method="serial",
+        )
+    except OSError as e:
+        return RebootResult(
+            success=False,
+            message=f"OS error: {e}",
+            method="serial",
+        )
+
+
+def reboot_zynq(
+    config: Config,
+    method: str = "auto",
+    timeout: int | None = None,
+    callback: ProgressCallback = None,
+) -> RebootResult:
+    """Reboot the Zynq device using the best available method.
+
+    Tries SSH first, falls back to serial if SSH is unavailable.
+
+    Args:
+        config: Application configuration.
+        method: Reboot method: 'auto', 'ssh', or 'serial'.
+        timeout: Seconds to wait for reboot.
+        callback: Optional progress callback.
+
+    Returns:
+        RebootResult with status.
+    """
+    timeout = timeout or config.reboot_timeout
+
+    if method == "ssh":
+        return reboot_via_ssh(config, timeout, callback)
+    elif method == "serial":
+        return reboot_via_serial(config, callback)
+
+    # Auto: try SSH first, then serial
+    result = reboot_via_ssh(config, timeout, callback)
+    if result.success:
+        return result
+
+    if callback:
+        callback("progress", "SSH failed, trying serial...")
+
+    return reboot_via_serial(config, callback)