Add Docker Compose dev configuration (docker-compose.dev.yml)

[landoyjx]

Provide a docker-compose.dev.yml file that spins up the server in a container with live-reload/volume mapping for local development. Include instructions in a README section.

Acceptance Criteria:

• docker-compose -f docker-compose.dev.yml up builds and starts the server
• Code changes are reflected without rebuilding the container (volume mount)
• SQLite file is persisted in a named volume or local directory so data survives container restarts

Test Cases:

• E2E/Manual: Start with docker-compose.dev.yml, create a todo, restart container, and verify todo persists
• E2E/Manual: Modify a source file and confirm the change is picked up by the running server