customModeModelChangedEventHandler may activate wrong model when BYOK and native models share a name

Summary

The customModeModelChangedEventHandler in ModelService resolves the model to activate by searching for the first map entry whose getModelName() matches the name extracted from the event payload (format: "<modelName> (<modelFamily>)").

If a BYOK model and a native Copilot model happen to share the same modelName, findModelKeyByName returns the first match regardless of provider, which can activate the wrong model.

Root cause

The custom-mode event protocol carries only a human-readable model name (plus family in parens). There is no provider or composite key in the payload, so a name-only lookup is inherently ambiguous when models share a name across providers.

Fix

Extend the custom-mode event protocol to carry the composite key (or at minimum the provider name alongside the model name), so customModeModelChangedEventHandler can do an unambiguous direct map lookup.

Related

• PR #246 (fixes the model-picker collision; this is a residual edge case in the custom-mode path)

Start in ModelService at customModeModelChangedEventHandler and findModelKeyByName, then trace the custom-mode event protocol and review PR #246 for the related model-picker collision fix. The work is complete when the event carries enough provider or composite-key information for an unambiguous direct lookup, including when BYOK and native models share a name.