Scaffold: agent starter kit (seeded from Ebb)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/gradle-serial.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+# Runs ./gradlew with the given arguments, one Gradle build at a time across every worktree and agent on this machine
+# (CLAUDE.md › Build and verify: parallel builds exhaust memory). Waits for a running build to finish, then runs.
+# Usage from any worktree root:  tools/gradle-serial.sh check
+lock=/tmp/kvitt-gradle.lock
+top=$(git rev-parse --show-toplevel) || exit 1
+while ! mkdir "$lock" 2>/dev/null; do
+  pid=$(cat "$lock/pid" 2>/dev/null)
+  if [ -n "$pid" ] && ! kill -0 "$pid" 2>/dev/null; then rm -rf "$lock"; continue; fi
+  sleep 5
+done
+echo $$ > "$lock/pid"
+trap 'rm -rf "$lock"' EXIT INT TERM HUP
+cd "$top" && ./gradlew "$@"