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.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -20,7 +20,7 @@ body:
       label: Preliminary Checks
       description: Please confirm you have completed these steps
       options:
-        - label: I have read the [Code of Conduct](.github/CODE_OF_CONDUCT.md)
+        - label: I have read the [Code of Conduct](https://github.com/wshobson/agents/blob/main/.github/CODE_OF_CONDUCT.md)
           required: true
         - label: >-
             I have searched existing issues to ensure this is not a duplicate

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -19,7 +19,7 @@ body:
       label: Preliminary Checks
       description: Please confirm you have completed these steps
       options:
-        - label: I have read the [Code of Conduct](.github/CODE_OF_CONDUCT.md)
+        - label: I have read the [Code of Conduct](https://github.com/wshobson/agents/blob/main/.github/CODE_OF_CONDUCT.md)
           required: true
         - label: >-
             I have searched existing issues to ensure this is not a duplicate

.github/ISSUE_TEMPLATE/new_subagent.yml

@@ -20,7 +20,7 @@ body:
       label: Preliminary Checks
       description: Please confirm you have completed these steps
       options:
-        - label: I have read the [Code of Conduct](.github/CODE_OF_CONDUCT.md)
+        - label: I have read the [Code of Conduct](https://github.com/wshobson/agents/blob/main/.github/CODE_OF_CONDUCT.md)
           required: true
         - label: >-
             I have reviewed existing subagents to ensure this is not a duplicate