Type menu change leaves a device configured=False, invisible to iter('self') — both #58 guards are structurally blind

[simons-plugins]

Live evidence from jarvis (2026-06-12, the energy-plug rig device, found while validating #60/#61).

What happened

The rig device node-matter Energy Plug (node 0x20, created as matterRelay) had its type changed to matterDimmer via Indigo's Edit Device Type menu. Result, captured by instrumented reconciles:

EXPERIMENT energy plug: type='matterDimmer' enabled=True configured=False
EXPERIMENT iter('self') returned 19 devices    # 20 exist — the flipped one is absent
EXPERIMENT index keys: [...]                   # (32, 1) missing

• Indigo mutates deviceTypeId immediately on menu selection — an unsaved (or guard-rejected) dialog still leaves the type changed, with configured=False.
• Unconfigured devices are excluded from iter("self") and never receive deviceStartComm.
• Therefore both Endpoint-mapping hardening: actuator duplicates, unknown-device fallback, type-edit guard #58 guards are blind: validateDeviceConfigUi only fires on a completed save, and the deviceStartComm backstop never runs.
• Downstream: the index loses the node, _unique_name can't see the name (it iterates the same collection), reconcile attempts a re-create, and Indigo rejects it server-side with NameNotUniqueError — previously a raw traceback every reconcile.

Shipped mitigation (PR #61)

_create_one now converts the collision into an actionable warning naming the device and the remedy (delete + reload; reconcile recreates it correctly).

Possibly worth doing later

• rebuild_index could additionally scan the unfiltered indigo.devices collection for our pluginId to spot configured=False strays and warn about them directly at reconcile (rather than waiting for the create collision).
• Docs: note in TESTING.md / README troubleshooting that the Type menu must never be used on Matter devices, and that the failure signature is this warning.

The remedy for the rig device itself: delete node-matter Energy Plug in the Indigo UI and reload the plugin.