test: run_tests.sh now supports testing specific directories

✅ Enhancement:
- tools/hako_check/run_tests.sh: Added argument handling (lines 97-116)
- Previously: Always ran all tests regardless of arguments
- Now: Can run specific test directory when provided as argument
- Example: bash run_tests.sh tools/hako_check/tests/HC021_analyzer_io_safety

✅ Use cases:
- Faster iteration during rule development
- Targeted debugging of specific rule tests
- CI/CD pipeline optimization

🤖 Generated with Claude Code (https://claude.com/claude-code)

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

tools/hako_check/run_tests.sh

@@ -94,10 +94,26 @@ run_case() {
   rm -f "$tmp_out" "$tmp_norm" "$tmp_json"
 }
 
-for d in "$TARGET_DIR"/*; do
+# Handle arguments: if provided, test only specified dirs; otherwise test all
+if [ $# -gt 0 ]; then
+  # Test only specified directories
+  for arg in "$@"; do
+    # Convert relative path to absolute
+    if [[ "$arg" == /* ]]; then
+      d="$arg"
+    else
+      d="$ROOT/$arg"
+    fi
+    [ -d "$d" ] || { echo "[TEST] not a directory: $d" >&2; continue; }
+    run_case "$d"
+  done
+else
+  # Test all directories
+  for d in "$TARGET_DIR"/*; do
     [ -d "$d" ] || continue
     run_case "$d"
-done
+  done
+fi
 
 if [ $fail -ne 0 ]; then
   echo "[TEST/SUMMARY] failures=$fail" >&2