fix: Use lowercase-with-hyphens skill names for Claude.ai compatibility

Fix skill names in SKILL.md frontmatter to comply with Claude.ai requirements:
"Skill name in SKILL.md can only contain lowercase letters, numbers, and hyphens."

## Changes

Updated skill names from "Title Case With Spaces" to "lowercase-with-hyphens":

1. "n8n Expression Syntax" → "n8n-expression-syntax"
2. "n8n MCP Tools Expert" → "n8n-mcp-tools-expert"
3. "n8n Workflow Patterns" → "n8n-workflow-patterns"
4. "n8n Validation Expert" → "n8n-validation-expert"
5. "n8n Node Configuration" → "n8n-node-configuration"

## Files Modified

- skills/n8n-expression-syntax/SKILL.md
- skills/n8n-mcp-tools-expert/SKILL.md
- skills/n8n-workflow-patterns/SKILL.md
- skills/n8n-validation-expert/SKILL.md
- skills/n8n-node-configuration/SKILL.md

## Distribution Packages

Regenerated all distribution zip files with corrected SKILL.md:
- dist/n8n-expression-syntax-v1.0.0.zip
- dist/n8n-mcp-tools-expert-v1.0.0.zip
- dist/n8n-workflow-patterns-v1.0.0.zip
- dist/n8n-validation-expert-v1.0.0.zip
- dist/n8n-node-configuration-v1.0.0.zip
- dist/n8n-mcp-skills-claude-code-v1.0.0.zip

Skills can now be uploaded to Claude.ai without naming errors.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

skills/n8n-validation-expert/SKILL.md

@@ -1,5 +1,5 @@
 ---
-name: n8n Validation Expert
+name: n8n-validation-expert
 description: Interpret validation errors and guide fixing them. Use when encountering validation errors, validation warnings, false positives, operator structure issues, or need help understanding validation results. Also use when asking about validation profiles, error types, or the validation loop process.
 ---