feat: Add production learnings to skills and optimize triggering (v1.5.0)

Incorporate real-world n8n workflow building experience into all 7 skills:
- SplitInBatches loop semantics, cross-iteration data, nested loops
- Google Sheets/Drive integration gotchas
- pairedItem, correct node references, float precision patterns
- Batch Processing as 6th core workflow pattern
- MCP tool parameter corrections (updates vs parameters, credential format)
- $env blocking awareness, bracket notation for special chars

Optimize all skill descriptions for better triggering accuracy:
- n8n-mcp-tools-expert: triggers on any n8n MCP tool usage
- n8n-workflow-patterns: triggers on workflow creation/design
- n8n-code-javascript: triggers on Code node usage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

build.sh

@@ -5,7 +5,7 @@
 set -e
 
 DIST_DIR="dist"
-VERSION="1.4.0"
+VERSION="1.5.0"
 
 echo "🔨 Building n8n-skills distribution packages..."