Add integration test for subagent-driven-development

Created full end-to-end integration test that executes a real plan
and verifies the new workflow improvements actually work.

New test: test-subagent-driven-development-integration.sh
- Creates real Node.js test project
- Generates implementation plan (2 tasks)
- Executes using subagent-driven-development skill
- Verifies 8 key behaviors:
  1. Plan read once at beginning (not per task)
  2. Full task text provided to subagents (not file reading)
  3. Subagents perform self-review
  4. Spec compliance review before code quality
  5. Spec reviewer reads code independently
  6. Working implementation produced
  7. Tests pass
  8. No extra features added (spec compliance)

Integration tests are opt-in (--integration flag) due to 10-30 min runtime.

Updated run-skill-tests.sh:
- Added --integration flag
- Separates fast tests from integration tests
- Shows note when integration tests skipped

Updated README with integration test documentation.

Run with:
  ./run-skill-tests.sh                # Fast tests only
  ./run-skill-tests.sh --integration  # Include integration tests

tests/claude-code/run-skill-tests.sh

@@ -26,6 +26,7 @@ fi
 VERBOSE=false
 SPECIFIC_TEST=""
 TIMEOUT=300  # Default 5 minute timeout per test
+RUN_INTEGRATION=false
 
 while [[ $# -gt 0 ]]; do
     case $1 in
@@ -41,17 +42,25 @@ while [[ $# -gt 0 ]]; do
             TIMEOUT="$2"
             shift 2
             ;;
+        --integration|-i)
+            RUN_INTEGRATION=true
+            shift
+            ;;
         --help|-h)
             echo "Usage: $0 [options]"
             echo ""
             echo "Options:"
-            echo "  --verbose, -v      Show verbose output"
-            echo "  --test, -t NAME    Run only the specified test"
-            echo "  --timeout SECONDS  Set timeout per test (default: 300)"
-            echo "  --help, -h         Show this help"
+            echo "  --verbose, -v        Show verbose output"
+            echo "  --test, -t NAME      Run only the specified test"
+            echo "  --timeout SECONDS    Set timeout per test (default: 300)"
+            echo "  --integration, -i    Run integration tests (slow, 10-30 min)"
+            echo "  --help, -h           Show this help"
             echo ""
             echo "Tests:"
-            echo "  test-subagent-driven-development.sh  Test subagent-driven-development workflow"
+            echo "  test-subagent-driven-development.sh  Test skill loading and requirements"
+            echo ""
+            echo "Integration Tests (use --integration):"
+            echo "  test-subagent-driven-development-integration.sh  Full workflow execution"
             exit 0
             ;;
         *)
@@ -62,11 +71,21 @@ while [[ $# -gt 0 ]]; do
     esac
 done
 
-# List of skill tests to run
+# List of skill tests to run (fast unit tests)
 tests=(
     "test-subagent-driven-development.sh"
 )
 
+# Integration tests (slow, full execution)
+integration_tests=(
+    "test-subagent-driven-development-integration.sh"
+)
+
+# Add integration tests if requested
+if [ "$RUN_INTEGRATION" = true ]; then
+    tests+=("${integration_tests[@]}")
+fi
+
 # Filter to specific test if requested
 if [ -n "$SPECIFIC_TEST" ]; then
     tests=("$SPECIFIC_TEST")
@@ -153,6 +172,12 @@ echo "  Failed:  $failed"
 echo "  Skipped: $skipped"
 echo ""
 
+if [ "$RUN_INTEGRATION" = false ] && [ ${#integration_tests[@]} -gt 0 ]; then
+    echo "Note: Integration tests were not run (they take 10-30 minutes)."
+    echo "Use --integration flag to run full workflow execution tests."
+    echo ""
+fi
+
 if [ $failed -gt 0 ]; then
     echo "STATUS: FAILED"
     exit 1