Clarify target terminal for command examples in `docs/contributing/set-up-dev-env.md`

[kosiew]

Description

Several code blocks in docs/contributing/set-up-dev-env.md were ambiguous about whether the commands should be executed on the host (external terminal) or inside the development container. Some label lines used # which is also the typical shell prompt for container examples, causing confusion for readers.

Reproduce

1. Open docs/contributing/set-up-dev-env.md.
2. Scan the command blocks that show prompts (for example, $ or #).
3. Observe that some label lines use # inline inside code blocks which looks like a prompt rather than a label.

Actual behavior

Some label lines appeared inside code blocks and started with #, making it unclear whether the # represented a shell prompt (container) or a label.

Expected behavior

Each command block should be clearly annotated with where it should be run. Labels should be placed outside of code blocks and be unambiguous, e.g.:

• "Run on host (external terminal):"
• "Run inside dev container (container terminal):"

docker version

n/a

docker info

n/a

Additional Info

No response