feat(webapp): one trace status and a full-width toolbar on the run page

The run page now shows one clear trace status next to Cancel and Replay:
whether the run is live, still loading, only partially shown, or failed
to load (with a retry). Search, filters and the run actions share a
single full-width toolbar, and a finished run no longer shows a spinner
on its root while its trace loads.

Mono-RevId: f853bcf7d20db0250625163bfb0936c72c5cb823

Author: Mariefay

.server-changes/run-page-trace-status.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: improvement
+---
+
+The run page shows one clear trace status next to Cancel and Replay: whether the run is live, still loading, only partially shown, or failed to load (with a retry). Search, filters and the run actions now share a single full-width toolbar.

apps/webapp/app/hooks/useProgressiveTrace.ts

@@ -80,8 +80,6 @@ export type ProgressiveTraceState = {
   linkedRunIdBySpanId: Record<string, string>;
   isComplete: boolean;
   isTruncated: boolean;
-  // Errors-only matches were capped; separate from `isTruncated`, which stops live reload.
-  errorsTruncated: boolean;
   loadFailed: boolean;
 };
 
@@ -99,7 +97,6 @@ function initialState(trace: ProgressiveTraceInput): ProgressiveTraceState {
     linkedRunIdBySpanId: trace.linkedRunIdBySpanId ?? {},
     isComplete: !trace.progressive?.hasMore,
     isTruncated: false,
-    errorsTruncated: false,
     loadFailed: false,
   };
 }
@@ -226,7 +223,6 @@ export function useProgressiveTrace(
       linkedRunIdBySpanId: view.linkedRunIdBySpanId,
       isComplete: prev.isComplete,
       isTruncated: prev.isTruncated,
-      errorsTruncated: prev.errorsTruncated,
       loadFailed: prev.loadFailed,
     }));
   }, []);
@@ -385,9 +381,6 @@ export function useProgressiveTrace(
       errorsFetchedRef.current = true;
       assembler.mergeChunk(data.events.map(toChunkEvent), { source: "errors" });
       rebuild(meta, assembler);
-      if (data.isTruncated) {
-        setState((prev) => (prev.errorsTruncated ? prev : { ...prev, errorsTruncated: true }));
-      }
     })();
 
     return () => {