fix: restore model activity reasoning stream

backend/src/routes/sessions.ts

@@ -69,8 +69,7 @@ export function sessionRoutes(
     const options = {
       provider: s.provider,
       model: s.model,
-      // Keep the saved preference in the manifest; F1 starts tool-first.
-      thinking: "off",
+      thinking: s.thinking,
       author: getUser(req).id,
       question: b.question,
     };
@@ -117,9 +116,7 @@ export function sessionRoutes(
     const options = {
       provider: saved?.provider,
       model: saved?.model,
-      // Phase 1 must reach a widget instead of exposing a long reasoning trace.
-      // The session keeps its saved preference for later turns.
-      thinking: "off",
+      thinking: saved?.thinking ?? settings.thinking,
       author: getUser(req).id,
       mode: "resume" as const,
     };