The session's Gamma Weather history, and the moments it said something new.

/api/gex/weather answers what the panel reads right now. This answers what happened while nobody was looking, which the header cannot: a word on a chip captures one slice of time, and someone returning to the page after two hours is asking about a pattern.

Both endpoints go through the same loader and the same classifier, so a bar described here and the same bar described there cannot disagree.

changes is not one entry per bar. An entry exists only where a label actually moved, so a quiet afternoon in one state produces a single line instead of fifty identical ones, and the trail stays readable at a glance. Every label is classified causally, from its bar and the ones before it, so the trail is not a hindsight summary. It is not a recording either: the session is reclassified on every read, so a bar the panel read while it was still filling can show a label here that the panel did not.

Same 400 / 404 / 409 semantics as the current-state endpoint.