chore: import upstream snapshot with attribution

scripts/clean.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# clean.sh — Remove ALL build artifacts, caches, and generated files.
+#
+# Usage: scripts/clean.sh
+#
+# Ensures every subsequent build starts from scratch — no cached .o files,
+# no stale node_modules, no leftover dist folders. This is the first step
+# in both scripts/test.sh and scripts/build.sh.
+
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+
+echo "=== Cleaning build artifacts ==="
+
+# C build artifacts
+rm -rf "$ROOT/build/c"
+
+# Frontend build artifacts
+rm -rf "$ROOT/graph-ui/dist"
+rm -rf "$ROOT/graph-ui/node_modules"
+
+# Root-level node artifacts (if any)
+rm -rf "$ROOT/node_modules"
+
+# Generated embedded assets (regenerated by embed-frontend.sh)
+rm -f "$ROOT/src/ui/embedded_assets.c"
+
+# Leftover test fixture dirs (C test suite sometimes creates these in CWD)
+find "$ROOT" -maxdepth 1 -type d \( -name 'cbm_*' -o -name 'cli-*' \) -exec rm -rf {} + 2>/dev/null || true
+
+# Leftover test fixture dirs in /tmp
+find /tmp -maxdepth 1 -type d \( -name 'cbm_*' -o -name 'cli-*' \) -user "$(id -u)" -exec rm -rf {} + 2>/dev/null || true
+
+echo "=== Clean complete ==="