feat(hub-guide): add 'ask when ambiguous' principle across skills

- Add principle #25 to engineering-principles: 'Ask When Ambiguous'
- Add 'Ask When Ambiguous' section to design-patterns and clean-architecture
- Update detect-project.sh hook to reinforce ask-don't-assume behavior

hooks/scripts/detect-project.sh

@@ -73,3 +73,4 @@ if [ -n "$SKILLS" ]; then
   echo "📐 [hub-guide] project-specific: ${SKILLS}"
 fi
 echo "📐 [hub-guide] Apply these best-practice rules throughout this session."
+echo "📐 [hub-guide] When in doubt about intent or approach — ask instead of assuming."