A label that displays a model name with smart truncation.
When the full provider:model text doesn't fit, the provider is dropped
first. If the bare model name still doesn't fit, it is left-truncated
with a leading ellipsis so the most distinctive tail stays visible.
When a reasoning effort is set, its label is appended to the model and participates in the same ladder: the effort suffix is preserved (with the model left-truncated to make room) and is only dropped once even the left-truncated model plus effort cannot fit.
Whatever text survives that ladder is also a hit target: clicking the model
span opens the model selector and clicking the effort span opens the reasoning
effort picker, via the _PICKER_ACTIONS app actions. A span that the ladder
dropped is not clickable, because only rendered text carries the metadata.
