chore(makefile): standardize grouped make help

[samzong]

📝 Description

Group make help output into sections driven by # ── Section ─ headers, with colored target names and trailing ## description comments, and make help the default goal so a bare make lists the available targets. The Chinese target comments are replaced with English descriptions, and the install and clean targets move into their sections. This gives every samzong repository the same discoverable make help layout.

🔄 Change Type

• 🧹 Maintenance - Chores, dependencies, housekeeping (chore: in commit)

📱 Platform Impact

• Build System - Changes affect Makefile, CI/CD, or build process

🧪 Testing

• Manual Testing - make and make help list all 16 public targets under their sections; make -n output of every target matches HEAD, so recipes are unchanged

📋 Checklist

• Self-review of code completed
• Commit messages follow Conventional Commits format

🎯 Release Notes Impact

• Skip Release Notes (minor changes only)