chore: repo scaffold, READMEs (EN/pt-BR), version pins, source fetch+vendorize scripts

- pins OpenBSD 8.0 tarballs (sha256) and Linux 7.3.4 as the port targets
- scripts/fetch-sources.sh (C3SL primary, cdn fallback), scripts/vendorize.sh
- scripts/{kernel-config,build-kernel}.sh for the VM-lab kernel

scripts/build-kernel.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# Build Linux 7.3.4 (VM-lab config) + collect boot artifacts into out/.
+set -euo pipefail
+REPO="$(cd "$(dirname "$0")/.." && pwd)"
+K="${KERNELDIR:-$(cd "$REPO/../linux-7.3.4" && pwd)}"
+cd "$K"
+"$REPO/scripts/kernel-config.sh" "${1:-}"
+JOBS="${JOBS:-$(($(nproc)-2))}"
+make -j"$JOBS" -s bzImage modules
+mkdir -p "$REPO/out"
+KVER="$(make -s kernelversion)"
+cp -f arch/x86/boot/bzImage "$REPO/out/linux-${KVER}-bzImage"
+cp -f System.map "$REPO/out/System.map"
+cp -f .config "$REPO/out/.config"
+make -s kernelrelease > "$REPO/out/kernelversion"
+sha256sum "$REPO/out/linux-${KVER}-bzImage" > "$REPO/out/bzImage.sha256"
+echo "KERNEL_BUILD_OK $(cat "$REPO/out/kernelversion")"