chore: import upstream snapshot with attribution

tools/detect_python.fish

@@ -0,0 +1,25 @@
+# This file should be sourced, not executed!
+#
+# This is a port of detect_python.sh. More information are provided there.
+
+set OLDEST_PYTHON_SUPPORTED_MAJOR 3
+set OLDEST_PYTHON_SUPPORTED_MINOR 10
+
+set -x ESP_PYTHON python
+
+for p_cmd in python3 python python3.10 python3.11 python3.12 python3.13;
+    $p_cmd --version >/dev/null 2>&1; or continue
+    echo "Checking \"$p_cmd\" ..."
+
+    $p_cmd -c "import sys; exit(1) if sys.version_info.major < int(\"$OLDEST_PYTHON_SUPPORTED_MAJOR\") else exit(0);"; or continue
+    $p_cmd -c "import sys; exit(1) if sys.version_info.minor < int(\"$OLDEST_PYTHON_SUPPORTED_MINOR\") else exit(0);"; or continue
+
+    set ESP_PYTHON $p_cmd
+    break
+end
+
+test -n "$ESP_PYTHON"; or echo "Python $OLDEST_PYTHON_SUPPORTED_MAJOR.$OLDEST_PYTHON_SUPPORTED_MINOR+ is not installed! Please see the documentation for how to install it."
+test -n "$ESP_PYTHON"; or exit 1
+
+$ESP_PYTHON --version
+echo "$ESP_PYTHON has been detected"