Revert experimental UI changes

vibn-frontend/app/api/chat/route.ts

@@ -1714,31 +1714,33 @@ export async function POST(request: Request) {
               temperature: 0.3,
               signal: clientSignal,
             });
-            if (summary.thoughts) {
-              assistantTimeline.push({
-                kind: "thought",
-                text: summary.thoughts,
-              });
-              emit({ type: "thinking", text: summary.thoughts });
-            }
-            
             if (summary.text && summary.text.trim()) {
-              assistantTimeline.push({ kind: "text", text: summary.text });
               assistantText += (assistantText ? "\n\n" : "") + summary.text;
               assistantTextSegments.push(summary.text);
               emit({ type: "text", text: summary.text });
             } else {
+              // Gemini returned empty — fall back to a deterministic but
+              // STRUCTURED build-health status (never a vague "didn't reach a
+              // clean stopping point"). It states what happened, what broke,
+              // and the next action, using the same signals as the telemetry
+              // stop_reason.
               const fallback = buildHealthStatus({
                 loopBreakReason,
                 hitRoundCap: maxToolRounds > 0 && round >= maxToolRounds,
                 lastError: extractLastToolFailure(messages),
                 toolCount: assistantToolCalls.length,
               });
-              assistantTimeline.push({ kind: "text", text: fallback });
               assistantText += (assistantText ? "\n\n" : "") + fallback;
               assistantTextSegments.push(fallback);
               emit({ type: "text", text: fallback });
             }
+            if (summary.thoughts) {
+              assistantTimeline.push({
+                kind: "thought",
+                text: summary.thoughts,
+              });
+              emit({ type: "thinking", text: summary.thoughts });
+            }
           } catch {
             const fallback = buildHealthStatus({
               loopBreakReason,
@@ -1771,12 +1773,7 @@ export async function POST(request: Request) {
                 temperature: 0.3,
                 signal: clientSignal,
               });
-              if (finalSummary.thoughts) {
-                assistantTimeline.push({ kind: "thought", text: finalSummary.thoughts });
-                emit({ type: "thinking", text: finalSummary.thoughts });
-              }
               if (finalSummary.text && finalSummary.text.trim()) {
-                assistantTimeline.push({ kind: "text", text: finalSummary.text });
                 assistantText +=
                   (assistantText ? "\n\n" : "") + finalSummary.text;
                 assistantTextSegments.push(finalSummary.text);

vibn-frontend/components/vibn-chat/chat-panel.tsx

@@ -284,11 +284,14 @@ function summarizeToolResult(result?: string): {
   }
 
   // Plain-text heuristics
+  // We explicitly ignore 'error' and 'exception' here because tools like dev_server_logs
+  // or browser_console legitimately return stack traces when working correctly.
+  // A raw string with 'error' inside it shouldn't auto-fail the tool execution pill.
   const lower = raw.toLowerCase();
   if (
-    /(econnrefused|enoent|error|failed|traceback|exception|not found|permission denied|cannot)/.test(
+    /(econnrefused|enoent|permission denied|command not found)/.test(
       lower,
-    )
+    ) && !raw.includes("dev_server_logs") && !raw.includes("browser_console")
   ) {
     return { ok: false, label: `Failed — ${firstLine(raw)}` };
   }
@@ -665,8 +668,6 @@ function Timeline({ entries, isActiveStream }: { entries: TimelineEntry[], isAct
  * bubble so each round of multi-tool-loop output reads as a discrete
  * step instead of concatenating into a wall of text.
  */
-
-
 function TimelineText({ text, isStreaming }: { text: string; isStreaming?: boolean }) {
   const proseWrap: React.CSSProperties = {
     overflowWrap: "anywhere",
@@ -1062,7 +1063,6 @@ export function ChatPanel({
       .catch(() => {});
   }, [projectId, workspace, status]);
   const [sending, setSending] = useState(false);
-  const [showScrollButton, setShowScrollButton] = useState(false);
   const [currentPhaseLabel, setCurrentPhaseLabel] = useState<string | null>(
     null,
   );
@@ -1551,12 +1551,15 @@ export function ChatPanel({
                       }
                     } catch {
                       // 2. If it's a raw string (like a bash crash), scan for fatal keywords
+                      // We skip this check for log-reading tools since they legitimately contain errors.
                       const lower = ev.result.toLowerCase();
                       if (
-                        lower.includes("error") ||
-                        lower.includes("failed") ||
-                        lower.includes("unexpected") ||
-                        lower.includes("not found")
+                        !ev.name?.includes("logs") &&
+                        !ev.name?.includes("console") &&
+                        (lower.includes("econnrefused") ||
+                         lower.includes("enoent") ||
+                         lower.includes("permission denied") ||
+                         lower.includes("command not found"))
                       ) {
                         isToolErr = true;
                       }
@@ -1893,11 +1896,6 @@ export function ChatPanel({
 
       {/* Messages */}
       <div
-        onScroll={(e) => {
-          const { scrollTop, scrollHeight, clientHeight } = e.currentTarget;
-          const distanceToBottom = scrollHeight - scrollTop - clientHeight;
-          setShowScrollButton(distanceToBottom > 150);
-        }}
         style={{
           flex: 1,
           minWidth: 0,
@@ -2127,8 +2125,6 @@ export function ChatPanel({
 
 
 
-
-
         <ProjectPreviewChatInputWrap unifiedShell={unifiedProjectShell}>
           {(selectToggle) => (
             <div