🔧 chore(templates): align agent templates and docs

- drop implementation-plan template and references
- add AGENT_RULES.local.md precedence in templates
- add plan meta guidance and CN updates

tests/templates/validate_project_templates.sh

@@ -79,7 +79,7 @@ echo ""
 echo "🔍 验证 memory-bank 模板"
 
 MEMORY_BANK_DIR="$TEMPLATES_DIR/memory-bank"
-for name in project-brief tech-stack architecture progress decisions implementation-plan; do
+for name in project-brief tech-stack architecture progress decisions; do
     validate_file_exists "$MEMORY_BANK_DIR/$name.template.md" "memory-bank/$name.template.md"
 done