Tango multi-device with id in device name

[gilesknap]

Parent

#351

What to build

The Tango transport exposes each configured controller as its own Tango device, with the controller's id forming the leading attribute-name segment of the device name. Existing Tango tooling (jive, atkpanel, archiver) sees one Tango device per controller.

Scope:

• Tango transport adopts the multi-controller connect() properly: iterates per-controller for device construction.
• Per-transport Tango id validator runs at connect() time: rejects illegal characters with a clear startup error.
• End-to-end multi-controller Tango scenario added covering: two controllers exposed as two distinct Tango devices with no clash.
• Tango transport test gains a per-transport id-validation case demonstrating the fail-fast behaviour.

User stories from #351 covered: 16, 17, 21.

Acceptance criteria

• One Tango server hosts N devices, one per controller, with id in the device name
• Tango id validator rejects illegal characters with a clear startup error
• Multi-controller Tango scenario test passes
• Tango transport test covers id-validation fail-fast
• Full test suite stays green

Blocked by

• Multi-controller foundation end-to-end via REST transport #353