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/startup-business-analyst/skills/startup-metrics-framework/SKILL.md

@@ -534,19 +534,6 @@ Burn: $180K/mo | Runway: 18 months
 - Growth rate or trend
 - Context (target, benchmark)
 
-## Additional Resources
-
-### Reference Files
-
-- **`references/metric-definitions.md`** - Complete definitions and formulas for 50+ metrics
-- **`references/benchmarks-by-stage.md`** - Target ranges for each metric by company stage
-- **`references/calculation-examples.md`** - Step-by-step calculation examples
-
-### Example Files
-
-- **`examples/saas-metrics-dashboard.md`** - Complete metrics suite for B2B SaaS company
-- **`examples/marketplace-metrics.md`** - Marketplace-specific metrics with examples
-- **`examples/investor-metrics-deck.md`** - How to present metrics for fundraising
 
 ## Quick Start
 
@@ -560,5 +547,3 @@ To implement startup metrics framework:
 6. **Review regularly** - Weekly for core metrics
 7. **Share with team** - Align on goals and progress
 8. **Update investors** - Monthly/quarterly reporting
-
-For detailed definitions, benchmarks, and examples, see `references/` and `examples/`.