fix: two-phase boot wait — don't stop on version when IP still pending

Previously the boot wait loop broke on the first detection of EITHER
IP or version. The Zynq firmware outputs its version string early in
the boot sequence (e.g. firmware header), while the board IP arrives
in a later burst via 'Boot=, IP=192.168.100.13, Ver=...'. The loop
would break on the version-only signal, leaving IP empty.

Changes:
1. Phase 1: log boot signal (version) but keep polling for IP
2. Phase 2: break only when IP address is actually found
3. After timeout: final check of latest_info for late-arriving IP
4. UART buffer fallback: parse all accumulated lines for IP
   (handles lines that arrived between the last poll and exit)
5. 3s pre-scan delay before UDP discover to let network stack settle
   (board's UDP server starts at the very end of boot sequence)

src/gui/main_window.py

@@ -1158,25 +1158,63 @@ class MainWindow(ctk.CTk):
         if uart_alive and _uart_src:
             self._log_message(f"  ⏳ Waiting for UART boot signal (max {boot_delay}s)...")
             elapsed = 0.0
+            boot_seen = False  # Phase 1 guard — log once, keep waiting for IP
             while elapsed < boot_delay:
-                info = _uart_src.latest_info if hasattr(_uart_src, 'latest_info') else _uart_src.get_latest_info()
-                if info and (info.ip_address or info.version):
+                info = (
+                    _uart_src.latest_info
+                    if hasattr(_uart_src, "latest_info")
+                    else _uart_src.get_latest_info()
+                )
+                # Phase 2: IP address found — definitive boot confirmation
+                if info and info.ip_address:
                     self._log_message(
                         f"  ✓ Boot detected after {elapsed:.1f}s"
                         f" (IP={info.ip_address}, Ver={info.version})"
                     )
                     discovered_ip = info.ip_address
                     break
+                # Phase 1: boot signal (version) seen but no IP yet — keep polling
+                if info and info.version and not boot_seen:
+                    boot_seen = True
+                    self._log_message(
+                        f"  ✓ Boot signal after {elapsed:.1f}s"
+                        f" (Ver={info.version}), waiting for IP..."
+                    )
                 time.sleep(0.5)
                 elapsed += 0.5
             else:
-                self._log_message(f"  ⏱ UART timeout — no boot signal in {boot_delay}s")
+                self._log_message(f"  ⏱ UART timeout — no IP in {boot_delay}s")
+                # Final check: IP may have arrived after the last poll
+                info = (
+                    _uart_src.latest_info
+                    if hasattr(_uart_src, "latest_info")
+                    else _uart_src.get_latest_info()
+                )
+                if info and info.ip_address:
+                    self._log_message(f"  IP recovered from latest UART info: {info.ip_address}")
+                    discovered_ip = info.ip_address
         else:
             self._log_message(f"  ⏳ UART unavailable — sleeping {boot_delay}s for boot...")
             time.sleep(boot_delay)
 
+        # Fallback: parse IP from accumulated UART buffer (lines may arrive
+        # after boot wait loop exited — e.g. "Board IP: 192.168.100.13")
+        if not discovered_ip and _uart_src:
+            all_lines = (
+                _uart_src.all_lines
+                if hasattr(_uart_src, "all_lines")
+                else []
+            )
+            if all_lines:
+                parsed = parse_boot_output(all_lines)
+                if parsed.ip_address:
+                    discovered_ip = parsed.ip_address
+                    self._log_message(f"  IP from UART buffer: {discovered_ip}")
+
         # Discover actual IP after reboot (may have changed via DHCP)
         if not discovered_ip:
+            self._log_message("  ⏳ Network stack — waiting 3s...")
+            time.sleep(3)
             self._log_message("  Scanning for Zynq IP (192.168.100.11–30)...")
             discovered_ip = self._discover_zynq_ip()
             if discovered_ip:

src/zynq_checker.py

@@ -11,6 +11,7 @@ from __future__ import annotations
 import os
 import re
 import subprocess
+import tempfile
 from dataclasses import dataclass, field
 from pathlib import Path
 from typing import Callable
@@ -88,7 +89,6 @@ def check_zynq_jtag(config: Config, callback: Callable | None = None) -> ZynqChe
 
     # Find vivado executable via Xilinx root scan
     vivado_path = get_vivado_path(
-        vitis_path=getattr(config, "vitis_path", ""),
         xilinx_root=getattr(config, "xilinx_path", ""),
     )
     if not vivado_path:
@@ -104,7 +104,7 @@ def check_zynq_jtag(config: Config, callback: Callable | None = None) -> ZynqChe
 
     # Create temporary TCL script
     tcl_content = _build_jtag_query_tcl()
-    tcl_path = Path("/tmp/zynq_jtag_check_{}.tcl".format(os.getpid()))
+    tcl_path = Path(tempfile.gettempdir()) / f"zynq_jtag_check_{os.getpid()}.tcl"
     try:
         tcl_path.write_text(tcl_content)