[codex] add section nav and docker deploy support

[xinyiklin]

Summary

• add a sidebar section navigator that tracks and jumps between resume sections
• add Docker production deployment support with ALLOWED_HOSTS host/origin guarding
• refresh README, gitignore/dockerignore, and agent docs for self-hosted/AWS work

Review notes

• fixed host guard behavior so bare loopback hosts like localhost still work behind host-port mappings
• kept bad Host and bad Origin requests blocked

Validation

• npm run build
• node --check server.mjs
• git diff --check
• production smoke on PORT=5199: Host localhost returned 200; bad Host and bad Origin returned 403
• Docker build attempted but Docker daemon was not running locally