Add Git submodule content management system

[meaningfool]

Summary

• Add meaningfool-writing repository as a Git submodule for content management
• Configure Astro to use content from submodule via writing collection
• Update GitHub Actions workflows to handle submodules properly
• Add automated submodule update workflow

Changes

• ✅ Created meaningfool-writing repository with sample content
• ✅ Added as submodule at src/content/writing
• ✅ Updated Astro content collections configuration
• ✅ Modified pages to use writing collection
• ✅ Updated deployment workflow to include recursive submodules
• ✅ Added automated content update workflow
• ✅ Tested local development and fresh clone workflow

Test Plan

• Local development server shows submodule content
• Articles render correctly with clean URLs
• Fresh clone with --recursive works
• Build completes successfully
• GitHub Pages deployment includes submodule content
• Automated workflows function correctly

Benefits

• Separates content management from site code
• Allows independent content workflows
• Maintains full version control for both content and code
• Enables automated content updates

🤖 Generated with Claude Code