Add lld-parking-lot module: thread-safe parking lot with Strategy, Observer and CAS-based spot claiming, 10 tests incl. 64-thread race

lld-parking-lot/scripts/run-all.sh

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+#!/usr/bin/env bash
+# Regenerates every transcript in output/. Needs JDK 21+ and Maven 3.9+.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+mkdir -p output
+./scripts/run.sh > output/01-walkthrough.txt 2>&1
+mvn -B -q test > /dev/null
+python3 - <<'PY' > output/02-test-results.txt
+import glob, xml.etree.ElementTree as ET
+total = fail = 0
+for f in sorted(glob.glob("target/surefire-reports/TEST-*.xml")):
+    for tc in ET.parse(f).getroot().iter("testcase"):
+        bad = tc.find("failure") is not None or tc.find("error") is not None
+        total += 1; fail += bad
+        print(("FAIL " if bad else "PASS ") + tc.get("name"))
+print(f"{total} tests, {fail} failures")
+PY

lld-parking-lot/scripts/run.sh

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+#!/usr/bin/env bash
+# Compiles with plain javac (no Maven needed) and runs the walkthrough. Needs JDK 21 or newer.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+rm -rf target/plain && mkdir -p target/plain
+javac -d target/plain $(find src/main/java -name '*.java')
+java -cp target/plain com.ankurm.interviewlab.parking.Demo