fix: resolve release workflow YAML parsing errors with script-based approach

Replace heredoc-in-command-substitution pattern with script-based release notes
generation to fix YAML parser interpretation issues.

Root cause:
- GitHub Actions YAML parser interprets heredoc content inside $() as YAML structure
- Line 149 error: parser expected ':' after '### Initial Release'
- Pattern: NOTES=$(cat <<EOF...) causes content to be parsed as YAML

Solution:
- Created scripts/generate-initial-release-notes.js (mirrors generate-release-notes.js)
- Script outputs markdown that YAML parser doesn't interpret
- Keeps --- separators (safe in script output, not in heredocs)
- Consistent pattern across workflow (all release notes from scripts)

Benefits:
- Fixes CI failures since Oct 24 (commit 0e26ea6)
- YAML validates successfully with Python yaml.safe_load()
- Easier to test and maintain release note generation
- No need to change --- to ___ separators

Testing:
- Script generates correct markdown locally
- YAML syntax validated
- TypeScript builds and type checks pass

Fixes: Release workflow runs 18806809439, 18806655633, 18806137471, etc.
Related: PR #371 (different approach attempted)

Concieved by Romuald Członkowski - www.aiadvisors.pl/en

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

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/release.yml

@@ -142,19 +142,13 @@ jobs:
           if [ -z "$PREVIOUS_TAG" ]; then
             echo "ℹ️ No previous tag found, this might be the first release"
 
-            # Get all commits up to current commit - use heredoc for multiline
-            NOTES=$(cat <<EOF
-### 🎉 Initial Release
-
-This is the initial release of n8n-mcp v$CURRENT_VERSION.
-
----
-
-**Release Statistics:**
-- Commit count: $(git rev-list --count HEAD)
-- First release setup
-EOF
-)
+            # Generate initial release notes using script
+            if NOTES=$(node scripts/generate-initial-release-notes.js "$CURRENT_VERSION" 2>/dev/null); then
+              echo "✅ Successfully generated initial release notes for version $CURRENT_VERSION"
+            else
+              echo "⚠️ Could not generate initial release notes for version $CURRENT_VERSION"
+              NOTES="Initial release v$CURRENT_VERSION"
+            fi
 
             echo "has-notes=true" >> $GITHUB_OUTPUT