feat(chat): share a chat by link — anonymous read-only /shared/<token> page, share/unshare

tests/unit/test_steering_toggle_removal.py

@@ -22,8 +22,9 @@ ASSETS = FRONTEND / "assets"
 
 HEADER_JS = ASSETS / "header.js"
 
-#: All seven pages carry the shared header block (phase 34's five pages
-#: + phase 35's git-sources page + phase 50's History page).
+#: All eight pages carry the shared header block (phase 34's five pages
+#: + phase 35's git-sources page + phase 50's History page +
+#: phase 51's shared page).
 PAGES = (
     FRONTEND / "index.html",
     FRONTEND / "sources.html",
@@ -32,6 +33,7 @@ PAGES = (
     FRONTEND / "login.html",
     FRONTEND / "tuning.html",
     FRONTEND / "history.html",
+    FRONTEND / "shared.html",
 )