fix: carry institutional→formal rename through analysis rename maps

Nathan renamed the Design gradient 'institutional' → 'formal' (v1.4.0).
The analysis scripts carry historical rename maps that route old data
(elite/institutional) into the current bicorder.json gradient names, and
those maps still stopped at 'institutional' — so old readings would have
silently misaligned against the v1.4.0 structure.

- bicorder_classifier.py / export_model_for_js.py: add
  institutional_vs_vernacular → formal_vs_vernacular, keep elite→formal
- json_to_csv.py TERM_RENAMES: same two-step route
- convert_csv_to_json.py GRADIENT_MAPPINGS: elite_vs_vernacular now maps
  to 'formal'
- bicorder_classifier.py demo ratings: use the current dimension name
- analysis/README.md: example run name 1.3.0 → 1.4.0

analysis/scripts/json_to_csv.py

@@ -24,7 +24,8 @@ from pathlib import Path
 # Map old term pairs to current column names (matches COLUMN_RENAMES in other scripts).
 # Keys are (term_left, term_right) as found in older JSON files.
 TERM_RENAMES = {
-    ('elite', 'vernacular'): ('institutional', 'vernacular'),
+    ('elite', 'vernacular'): ('formal', 'vernacular'),
+    ('institutional', 'vernacular'): ('formal', 'vernacular'),
     ('exclusive', 'non-exclusive'): ('monopolistic', 'pluralistic'),
     ('insufficient', 'sufficient'): ('sufficient', 'limited'),  # note: order swapped in old versions
     ('Kafka', 'Whitehead'): ('restraining', 'liberating'),