fix(vitis): add xsct fallback for impact detection in Xilinx 2023.2

- vitis_checker: shutil.which() + xsct fallback for impact detection
- flash_programmer: _get_impact_path now checks xsct as fallback
- bitstream_programmer: _get_impact_path now checks xsct as fallback
- GUI: show '(via xsct)' alias note when xsct replaces impact
- ToolStatus: add 'alias' field for tracking which executable was found

src/bitstream_programmer.py

@@ -33,6 +33,7 @@ ProgressCallback = Callable[[str, str], None] | None
 def _get_impact_path(vitis_path: str) -> str | None:
     """Find the impact executable path.
 
+    Tries 'impact' first, then falls back to 'xsct' (Xilinx 2023.2+).
     Uses shutil.which() for cross-platform compatibility,
     then falls back to common Vitis paths.
 
@@ -40,18 +41,21 @@ def _get_impact_path(vitis_path: str) -> str | None:
         vitis_path: Vitis installation path.
 
     Returns:
-        Path to impact executable, or None if not found.
+        Path to impact or xsct executable, or None if not found.
     """
-    path = shutil.which("impact")
-    if path:
-        return path
+    # Try shutil.which for impact, then xsct as fallback
+    for tool in ("impact", "xsct"):
+        path = shutil.which(tool)
+        if path:
+            return path
     if vitis_path:
-        candidate = Path(vitis_path) / "bin" / "impact"
-        if candidate.exists():
-            return str(candidate)
-        candidate = Path(vitis_path) / "bin" / "impact.exe"
-        if candidate.exists():
-            return str(candidate)
+        bin_dir = Path(vitis_path) / "bin"
+        if bin_dir.exists():
+            for tool in ("impact", "xsct"):
+                for ext in ("", ".exe"):
+                    candidate = bin_dir / f"{tool}{ext}"
+                    if candidate.exists():
+                        return str(candidate)
     common_paths = [
         "/opt/xilinx/bin/impact",
         os.path.expanduser("~/Xilinx/Vitis/bin/impact"),