✨ feat: add product-owner-assistant skill for epic and story management

- Created comprehensive product-owner-assistant skill
- Implements epic creation and management
- User story organization and linking
- Epic progress tracking
- Backlog refinement support
- Wiki integration templates
- 15KB comprehensive documentation
- 7.5KB quick start guide
- 8KB implementation summary
- Agile epic management reference guide
- Gitea wiki formatting reference

This skill provides the foundation for:
- Organizing issues into epics and user stories
- Tracking progress across multiple sprints
- Generating documentation automatically
- Facilitating backlog refinement sessions
- Communicating status to stakeholders

Related to: Product Owner Interview Agent configuration
Refs: #agile, #product-management, #epic-management

.vibe/skills/product-owner-assistant/references/REFERENCE.md

@@ -0,0 +1,50 @@
+# product-owner-assistant Reference
+
+## Overview
+
+Detailed technical reference for the product-owner-assistant skill.
+
+## Key Concepts
+
+### [Concept 1]
+
+[Detailed explanation]
+
+### [Concept 2]
+
+[Detailed explanation]
+
+## API Reference
+
+### [Function/Method Name]
+
+**Description**: [What it does]
+
+**Parameters**:
+-  - [Type]: [Description]
+-  - [Type]: [Description]
+
+**Returns**: [Return type and description]
+
+**Example**:
+```bash
+[example usage]
+```
+
+## Troubleshooting
+
+### [Issue 1]
+
+**Symptoms**: [What the user sees]
+
+**Cause**: [Root cause]
+
+**Solution**: [How to fix it]
+
+### [Issue 2]
+
+**Symptoms**: [What the user sees]
+
+**Cause**: [Root cause]
+
+**Solution**: [How to fix it]