Add per-class recall and F1 across the panel; fit the banner title

README.md

@@ -105,7 +105,8 @@ CAMEO ships no train/test partition, and the usual way to make one — a ran
 
 </details>
 
-### Per class, across the panel
+<details>
+<summary><b>Per class, across the panel</b> &mdash; recall and F1 for every class on every test set</summary>
 
 <img src="assets/classes.svg" alt="Per-class recall and F1" width="100%">
 
@@ -113,6 +114,8 @@ Each card leads with the macro-F1 for that set; the rows are the detail behind i
 
 Each set keeps its own class list: the spontaneous corpus has four classes and the other two have seven, and there is no correspondence between `positive` and any single one of `happiness`/`enthusiasm` to line them up with.
 
+</details>
+
 ### Per-class recall on spontaneous speech
 
 | class | this model | previous release |