Enabling MSB node from README

[b-garbacz]

Description

1. Please see README file, and update it so that starting the node is easy in every scenario (mainnet/testnet, with/without RPC, env-based, Docker, etc.). If you want to introduce a consistent pattern that simplifies the startup process across all cases, feel free to do, any improvement is welcome.

2. Please make sure the README is updated accordingly (commands, examples, and expected behavior).

3. I would like to recommend to create a new task Enabling MSB node from README, to validate the documentation end-to-end. The goal is to be 100% sure that:

   • the documented commands actually work,
   • the built Docker image runs correctly,
   • users should be able to choose whether the service binds to localhost or 0.0.0.0. When running inside a container, the node should bind to 0.0.0.0 by default so it is reachable from the host through published ports. On the host side, exposure should remain configurable (for example, publish the port on 127.0.0.1/localhost for local only access, or on 0.0.0.0 to expose it externally). But again user should be aware what it is selecting.

Originally posted by @b-garbacz in #488 (comment)

Acceptance Criteria

• All README commands work end-to-end (host + Docker).
• Docker image builds and runs successfully.
• If something does not work, then update README to the working version of the command/instruction.