Split into per-article modules and add the method-security module

Moves the existing virtual-thread/context-propagation project into
context-propagation/ and adds method-security/ for the Spring Security 7
method-security article: nine runnable demos, fourteen assertions, and every
transcript the article quotes, regenerated by scripts/run-all.sh.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RSrsDSRKVsY588yFiMJMo9

method-security/scripts/run-all.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# Compiles this module twice -- once with -parameters and once without -- runs all nine demos
+# plus the JUnit suite, and regenerates every file in docs/output/.
+#
+# Requires JDK 25 (no preview features needed; the sibling context-propagation module does).
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+mvn -q dependency:build-classpath -Dmdep.outputFile=cp.txt
+CP=$(cat cp.txt)
+
+rm -rf target/classes target/classes-noparams
+mkdir -p target/classes target/classes-noparams docs/output
+
+# -parameters is what makes #owner resolve to "owner" instead of "arg0". Demo 9 is run from
+# both builds so the difference is a diff, not a claim.
+javac --release 25 -parameters -cp "$CP" -d target/classes $(find src/main -name '*.java')
+javac --release 25 -cp "$CP" -d target/classes-noparams $(find src/main -name '*.java')
+
+run() { # run <class-simple-name> <output-file> [classes-dir]
+  local demo="$1" out="docs/output/$2" dir="${3:-target/classes}"
+  echo "Running $demo -> $out"
+  # stderr is kept: Spring's own CGLIB warning about final methods is part of the evidence.
+  java -cp "$dir:$CP" "com.ankurm.methodsec.$demo" 2>&1 \
+    | grep -v '^Picked up JAVA_TOOL_OPTIONS' > "$out"
+}
+
+run Demo1AnnotationsInAction  demo1.txt
+run Demo2SelfInvocation       demo2.txt
+run Demo3NonProxyable         demo3.txt
+run Demo4SpelReference        demo4.txt
+run Demo5FilteringTraps       demo5.txt
+run Demo6InterceptorOrder     demo6.txt
+run Demo7DeniedHandling       demo7.txt
+run Demo8MetaAnnotations      demo8.txt
+run Demo9ParameterNames       demo9-with-parameters.txt    target/classes
+run Demo9ParameterNames       demo9-without-parameters.txt target/classes-noparams
+
+echo "Running JUnit trap suite -> docs/output/tests.txt"
+mvn -q test > /tmp/ms-mvn-test.txt 2>&1 || true
+{
+  echo "mvn test -- MethodSecurityTrapsTest (14 tests pinning every claim the demos print)"
+  echo
+  cat target/surefire-reports/com.ankurm.methodsec.MethodSecurityTrapsTest.txt
+} > docs/output/tests.txt
+rm -f /tmp/ms-mvn-test.txt
+
+echo
+echo "Regenerated:"
+ls -1 docs/output/