refactor(skills): drop The Bottom Line recap from writing-skills

Restates the Iron Law, the RED-GREEN-REFACTOR mapping, and the
TDD-for-docs framing, all stated in full earlier in the file.

skills/writing-skills/SKILL.md

@@ -677,13 +677,3 @@ How future agents find your skill:
 6. **Loads example** (only when implementing)
 
 **Optimize for this flow** - put searchable terms early and often.
-
-## The Bottom Line
-
-**Creating skills IS TDD for process documentation.**
-
-Same Iron Law: No skill without failing test first.
-Same cycle: RED (baseline) → GREEN (write skill) → REFACTOR (close loopholes).
-Same benefits: Better quality, fewer surprises, bulletproof results.
-
-If you follow TDD for code, follow it for skills. It's the same discipline applied to documentation.