Learn: rework binning and linked-views lessons

docs/architecture/11-learning-section.md

@@ -42,7 +42,11 @@ Inside a `:::progression`, each `##` heading is a stage: heading → tab label,
 the following fenced `vega-lite` block → spec. A `:::data` block names datasets once for the
 whole lesson; specs reference them with `{ "data": { "name": … } }` and `injectDatasets`
 merges the rows in at render time — so a shared dataset isn't repeated per stage, and the
-source pane keeps a stage's grammar legible instead of burying it under data.
+source pane keeps a stage's grammar legible instead of burying it under data. Every lesson
+uses the `:::data` form (never per-stage inline rows), targets a misconception rather than
+a chart type, and closes with a "take it further" prose beat that leans on the per-stage
+"Open in Astrolabe" links — the roster and per-lesson briefs live in
+`docs/exploration/lessons-roadmap.md`.
 
 ## The pipeline