fix(web): unlock transcript scroll after Discussion and label the model pill

The reasoning boxes in the Discussion exchange used overscroll-behavior:
contain, so a wheel-up over any of them never reached the transcript
scroller once the run had finished. Drop the containment; the pane's
nested-scroller check already hands off correctly.

While a Discussion is armed or running the composer model pill now reads
"Discussion" and opens the Discussion dialog instead of the model
dropdown, so the next reply's source is not misread as the session model.

Author: elkaix

.changeset/discussion-scroll-and-model-pill.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Fix the transcript not scrolling up after a Discussion finishes, and show "Discussion" on the composer model pill while a Discussion is armed or running.

apps/pythinker-code/dist-web/.web-bundle-manifest.json

@@ -1,4 +1,4 @@
 {
-  "sourceHash": "ac853c2bfa5acefa3e8cebfcf5ef58593d5a08092fb9254a52311bb8be2c4aca",
+  "sourceHash": "23b6e27ab9a10caebf97869285a37d681a65f9f0f6aec665f9595ead25230d12",
   "sourceFileCount": 418
 }