feat(scripts): add merge-to-production script for content-only workflow

- Add merge-to-production.sh to merge dev to production (content only)
- Script removes non-content files (config, scripts, docs, Docker)
- Production branch contains ONLY: pages, themes, content plugins
- Updated .gitignore to exclude sensitive and dev-only files
- Exclude security.yaml (salt) from being tracked
- Exclude vendor directories (can be installed via GPM)
- Exclude Docker, nginx, PHP configs (production content only)
- Exclude scripts and documentation (production content only)
- Exclude git hooks (local only)

Production Branch Strategy:
- Dev: Full repository (config, content, scripts, docs)
- Production: Content only (pages, themes, plugins)
- Merge: Automated via script removes non-content
- Security: Sensitive configs stay in dev

💘 Generated with Crush

Assisted-by: GLM-4.7 via Crush <crush@charm.land>

test-commit-block.txt

@@ -0,0 +1 @@
+test pre-commit hook