feat: add build numbering

scripts/bump-build.sh

@@ -0,0 +1,44 @@
+#!/bin/sh
+# bump-build.sh - Increment the MontaukOS kernel build number.
+#
+# Reads the current MONTAUK_BUILD_NUMBER from the given header, increments it,
+# and rewrites the header in place. Invoked by kernel/GNUmakefile whenever the
+# kernel or userspace sources change, so the build number reflects real builds.
+#
+# Usage: ./scripts/bump-build.sh <path-to-BuildNo.hpp>
+
+set -e
+
+HDR="$1"
+if [ -z "$HDR" ] || [ ! -f "$HDR" ]; then
+    echo "bump-build.sh: header not found: $HDR" >&2
+    exit 1
+fi
+
+cur=$(sed -n 's/^#define MONTAUK_BUILD_NUMBER \([0-9][0-9]*\).*/\1/p' "$HDR")
+if [ -z "$cur" ]; then
+    echo "bump-build.sh: could not parse MONTAUK_BUILD_NUMBER in $HDR" >&2
+    exit 1
+fi
+
+next=$((cur + 1))
+
+cat > "$HDR" <<EOF
+/*
+    * BuildNo.hpp
+    * Monotonic kernel build number.
+    *
+    * This file is the source of truth for the build number. It is regenerated
+    * (incremented) by scripts/bump-build.sh whenever the kernel or userspace
+    * sources change, via a rule in kernel/GNUmakefile. Do not edit the number
+    * by hand; the build system manages it.
+    *
+    * Copyright (c) 2026 Daniel Hammer
+*/
+
+#pragma once
+
+#define MONTAUK_BUILD_NUMBER $next
+EOF
+
+echo "  BUILD   $cur -> $next"