fix(gui): surface Logs failures when refresh is off and resync section tabs

Announce stale-log errors immediately when auto-refresh is disabled, and pick the heading nearest the reading line when a scroll-lock timeout fires.

Author: Wibias

gui/src/components/section-tabs.tsx

@@ -43,17 +43,19 @@ export function SectionTabs({
   /** Timeout path: drop the click lock and re-read the visible section. */
   const expireScrollLock = useCallback(() => {
     clearScrollLock();
-    // If the user interrupted smooth scroll, the target may never intersect — without a
-    // resync `active` would stay on the clicked tab while another section is on screen.
+    // If the user interrupted smooth scroll, the target may never cross the observer threshold —
+    // without a resync `active` would stay on the clicked tab while another section is on screen.
+    // Prefer the heading nearest the sticky-strip reading line (not only those with top <= 120),
+    // so a destination that stopped mid-viewport still wins over an off-screen prior heading.
     let bestId: string | null = null;
-    let bestTop = Number.NEGATIVE_INFINITY;
+    let bestDistance = Number.POSITIVE_INFINITY;
+    const readingLine = 72;
     for (const item of items) {
       const node = document.getElementById(sectionAnchorId(scope, item.id));
       if (!node) continue;
-      const top = node.getBoundingClientRect().top;
-      // Match the observer bias: prefer a heading near the top of the viewport.
-      if (top <= 120 && top > bestTop) {
-        bestTop = top;
+      const distance = Math.abs(node.getBoundingClientRect().top - readingLine);
+      if (distance < bestDistance) {
+        bestDistance = distance;
         bestId = item.id;
       }
     }

gui/src/pages/Logs.tsx

@@ -468,7 +468,10 @@ export default function Logs({ apiBase }: { apiBase: string }) {
   } else if (settledFailure && failureStreak.error !== logsState.error) {
     setFailureStreak(previous => ({ error: logsState.error, count: previous.count + 1 }));
   }
-  const pollFailing = failureStreak.count >= STALE_POLL_FAILURE_LIMIT;
+  // Auto-refresh off: one settled failure is enough — there is no next poll to recover quietly.
+  const pollFailing =
+    failureStreak.count >= STALE_POLL_FAILURE_LIMIT
+    || (!autoRefresh && settledFailure);
 
   const detailInfo = detail ? statusCodeInfo(detail.status, locale) : null;
   const conversationQuery = conversationFilter.trim();
@@ -635,8 +638,8 @@ export default function Logs({ apiBase }: { apiBase: string }) {
           </button>
         </Notice>
       )}
-      {/* A run of failed polls is no longer transient: say the rows below are stale rather than
-          letting them read as current. Cleared by the first successful poll. */}
+      {/* Stale rows after a sustained poll outage, or any settled failure while auto-refresh is
+          off (no next tick will recover). Cleared by the first successful fetch. */}
       {pollFailing && logs.length > 0 && (
         <Notice tone="err">
           {t("logs.loadError")}{" "}