fix(skills): add Anti-Patterns sections, fix descriptions, quality checks, and required inputs

- Add Anti-Patterns section (3-5 binary checkboxes) to all modified skills
- Fix Quality Checks to use binary checkbox format where needed
- Rewrite descriptions to verb-when-produces format where needed
- Add Required Inputs sections to skills missing them
- Fix email-triage frontmatter YAML quoting

https://claude.ai/code/session_01MuGKn3a3Gbqoe8uM5Lmuqt

skills/sprint-velocity-analysis/SKILL.md

@@ -261,3 +261,11 @@ If cycle time data was not provided: *Cycle time data was not included in this a
 - [ ] Next-sprint capacity forecast uses historical average as the baseline and deducts specific known reducers
 - [ ] Health diagnosis table uses Red/Yellow/Green with evidence cited in the Evidence column — no unsupported scores
 - [ ] If metrics are missing (cycle time, blocker log), the report explicitly calls them out as recommended additions
+
+## Anti-Patterns
+
+- [ ] Do not generate the velocity chart from placeholder data — it must reflect the actual sprint data provided
+- [ ] Do not diagnose trend direction without computing trailing vs leading averages — "it looks like it's declining" is not a diagnosis
+- [ ] Do not list carry-over as a generic observation — identify root cause categories with counts for the analysis to be actionable
+- [ ] Do not produce recommendations without a named owner, a start date, and a measurable target
+- [ ] Do not score health dimensions without citing evidence in the Evidence column — unsupported Red/Yellow/Green scores are not credible