feat: Add 'What is NOT a Semantic Anchor?' learning section

[raifdmueller]

Changes

Extended the About page with a comprehensive section explaining what does NOT qualify as a semantic anchor.

New Content

Counter-Examples Table:

• TLDR, ELI5, "Keep it short", "Best practices", "Modern approach", "Make it simple"
• Each with clear explanation of why it doesn't qualify

Good vs. Bad Comparisons:
Collapsible section with 3 detailed examples:

1. Testing: "Write good tests" ❌ vs. "TDD, London School" ✅
2. Communication: "Keep it short" ❌ vs. "Pyramid Principle" ✅
3. Code Quality: "Best practices" ❌ vs. "SOLID Principles" ✅

Testing Methodology:

• How to test if a term qualifies as a semantic anchor
• Clear checklist of what to look for in LLM responses

Why This Helps

• New users understand the quality criteria through negative examples
• Contributors can self-validate before proposing new anchors
• Clarity on the difference between instructions and semantic anchors
• Educational value - teaches through comparison

Location

docs/about.adoc - Section added after "Quality Criteria" and before "How to Use This Catalog"

All content is visible on the live About page at #/about

Preview

The section includes:

• 📊 Comparison table with 6 counter-examples
• 🔍 Detailed good/bad comparisons (collapsible)
• ✅ Testing checklist for potential anchors
• 💡 Key conceptual difference explanation