feat: containerize QuickNotes for lab 6

[tivdzualubem]

Summary

• add a multi-stage Dockerfile for QuickNotes
• build a static, stripped Go binary using Go 1.24.13
• use a distroless non-root runtime image
• add Docker Compose configuration with healthcheck and persistent named volume
• apply container hardening controls
• document Task 1, Task 2, persistence tests, security checks, and Trivy results

Validation

• final image size: 12.91 MiB
• /health endpoint: passed
• /notes endpoint: passed
• direct docker run test: passed
• Compose healthcheck: healthy
• persistence across docker compose down and up: passed
• data removal after docker compose down -v: passed
• non-root runtime: verified
• read-only root filesystem: verified
• all capabilities dropped: verified
• no-new-privileges: verified
• Trivy 0.59.1 scan completed

Files

• app/Dockerfile
• compose.yaml
• submissions/lab6.md