Fix robot joint motion workflows

[temiroff]

What changed

• Replace the simulated joint-state path in Move a Robot Joint with the reusable Robot driver path.
• Add visible Joint name, Armed, and Position angle value nodes.
• Wire robot descriptors into joint state and motion nodes and honor their host, transport, and topic settings.
• Block armed motion with an actionable report when the selected robot driver is not ready.
• Add explicit Armed controls to the joint-slider and mobile-base templates.

Why

The old workflow could publish to /joint_commands with no physical driver subscriber while reading a simulated three-joint /joint_states stream. Robot descriptor defaults could also override the selected robot connection instead of following it.

Impact

The single-joint workflow now starts and verifies the real driver path, uses all six SO-ARM101 joints, and exposes clear reusable controls while remaining disarmed by default.

Checks

• python -m pytest packages/blacknode-controllers/tests -q — 51 passed
• affected workflow validation — clean