fix(skills): remove phantom resource references and fix CoC links (#447)

Remove references to non-existent resource files (references/, assets/,
scripts/, examples/) from 115 skill SKILL.md files. These sections
pointed to directories and files that were never created, causing
confusion when users install skills.

Also fix broken Code of Conduct links in issue templates to use
absolute GitHub URLs instead of relative paths that 404.

plugins/business-analytics/skills/data-storytelling/SKILL.md

@@ -445,9 +445,3 @@ Present ranges:
 - **Don't use jargon** - Match audience vocabulary
 - **Don't show methodology first** - Context, then method
 - **Don't forget the narrative** - Numbers need meaning
-
-## Resources
-
-- [Storytelling with Data (Cole Nussbaumer)](https://www.storytellingwithdata.com/)
-- [The Pyramid Principle (Barbara Minto)](https://www.amazon.com/Pyramid-Principle-Logic-Writing-Thinking/dp/0273710516)
-- [Resonate (Nancy Duarte)](https://www.duarte.com/resonate/)

plugins/business-analytics/skills/kpi-dashboard-design/SKILL.md

@@ -420,9 +420,3 @@ for alert in alerts:
 - **Don't use 3D charts** - They distort perception
 - **Don't hide methodology** - Document calculations
 - **Don't ignore mobile** - Ensure responsive design
-
-## Resources
-
-- [Stephen Few's Dashboard Design](https://www.perceptualedge.com/articles/visual_business_intelligence/rules_for_using_color.pdf)
-- [Edward Tufte's Principles](https://www.edwardtufte.com/tufte/)
-- [Google Data Studio Gallery](https://datastudio.google.com/gallery)