fix(eta): show 'Scanning…' during Phase-2 online scan instead of 'Calculating…'

During the parallel online scan, state.totalNodes is 0 (set only post-scan,
pipeline.js ~802) and no node-test completions feed the ETA window, so the ETA
is genuinely incomputable. The bare 'Calculating…' (admin) / 'ETA —' (live) read
as frozen for the whole scan — minutes when many nodes are offline. Now both
surfaces show 'Scanning…' while totalNodes<=0 and running, then fall through to
'Calculating…' (population known, <2 completions) and the live countdown. No
change to the ETA math, ring, server, or TEST RUN paths.

Author: Sentinel-Bluebuilder

admin.html

@@ -1515,7 +1515,15 @@ <h1 style="margin:0;flex:0 0 auto">SENTINEL NODE TEST</h1>
         const rem = Math.max(0, _etaAnchor.remainingMs - (Date.now() - _etaAnchor.at));
         const h = Math.floor(rem / 3600000), m = Math.floor((rem % 3600000) / 60000), s = Math.floor((rem % 60000) / 1000);
         el.textContent = `${String(h).padStart(2,'0')}:${String(m).padStart(2,'0')}:${String(s).padStart(2,'0')}`;
+      } else if (!Number.isFinite(state.totalNodes) || state.totalNodes <= 0) {
+        // No testable population established yet → we're still in the Phase-2
+        // online scan (totalNodes is only set post-scan, pipeline.js ~line 802).
+        // ETA is genuinely incomputable here (no completions to measure), so say
+        // "Scanning…" rather than "Calculating…" so it doesn't read as frozen.
+        el.textContent = 'Scanning…';
       } else {
+        // Population known but <2 fresh completions in the ETA window → a real
+        // rate can't be derived yet. This clears after the first couple nodes.
         el.textContent = 'Calculating...';
       }
     }

live.html

@@ -1739,6 +1739,13 @@ <h1 class="live-page-title">
           const m = Math.floor((rem % 3600000) / 60000);
           const s = Math.floor((rem % 60000) / 1000);
           etaEl.textContent = `ETA ${String(h).padStart(2,'0')}:${String(m).padStart(2,'0')}:${String(s).padStart(2,'0')}`;
+        } else if (_liveState && _liveState.status === 'running'
+                   && (!Number.isFinite(Number(_liveState.totalNodes)) || Number(_liveState.totalNodes) <= 0)) {
+          // Running but no testable population yet → still in the Phase-2 online
+          // scan (totalNodes is only set post-scan, pipeline.js ~line 802). ETA is
+          // genuinely incomputable (no completions to measure), so show "Scanning…"
+          // rather than a frozen-looking "ETA —". Parity with admin.html updateETA.
+          etaEl.textContent = 'ETA Scanning…';
         } else {
           etaEl.textContent = 'ETA —';
         }