fix(control-pane): replace stale live-region guidance when a poll fails

The live region announced the advisory and steering state on every
change, but a failed or invalid poll only set the visible status to
offline. The live region kept the last known message, so during an
outage a screen-reader user could still hear "No steering is required"
from a poll that had already failed. That is worse than silence,
because stale guidance reads as current.

Route announcements through a single helper and have the failure path
replace the guidance with a message saying the data is unavailable and
the counts are unknown. The helper still suppresses a repeat of the
same message, so a continuing outage stays quiet and recovery speaks
again.

Cover the success then failure and failure then recovery sequences at
runtime. Reverting just the failure-path announcement fails the new
assertion, and the unmutated view passes all of them.

Co-authored-by: CommandCodeBot <noreply@commandcode.ai>

scripts/lib/control-pane/control-plane-view-ui.js

@@ -83,8 +83,8 @@ function renderControlPlaneViewHtml() {
   var canvas = document.getElementById('c');
   var ctx = canvas.getContext('2d');
   var view = { tasks: [], lanes: [], pairs: [], events: [], projection: { agents: [] }, thresholds: { ta: 0.35, ra: 0.7 } };
-  // Last advisory/steering pair handed to the live region, so a poll that
-  // changes nothing stays silent.
+  // Last message handed to the live region, so a poll that changes nothing
+  // stays silent.
   var lastSpoken = null;
 
   function resize() {
@@ -240,6 +240,15 @@ function renderControlPlaneViewHtml() {
     });
   }
 
+  // Polling runs every few seconds, so only speak when the advisory and
+  // steering counts actually move. Repeating an unchanged summary would talk
+  // over the operator without telling them anything new.
+  function announce(message) {
+    if (message === lastSpoken) return;
+    lastSpoken = message;
+    document.getElementById('announce').textContent = message;
+  }
+
   function apply(data) {
     if (!data || data.schemaVersion !== 'ecc.control-plane.view.v1' ||
         !['tasks', 'lanes', 'pairs', 'events'].every(function (key) { return Array.isArray(data[key]); }) ||
@@ -259,17 +268,9 @@ function renderControlPlaneViewHtml() {
       (c.advisories || 0) + ' advisories (' + (c.resolutions || 0) + ' steering)' +
       (view.inventory && view.inventory.status !== 'ok' ? ' | inventory ' + view.inventory.status : '');
 
-    // Polling runs every few seconds, so only speak when the advisory and
-    // steering counts actually move. Repeating an unchanged summary would talk
-    // over the operator without telling them anything new.
-    var speaker = document.getElementById('announce');
-    var spoken = (c.advisories || 0) + '/' + (c.resolutions || 0);
-    if (spoken !== lastSpoken) {
-      lastSpoken = spoken;
-      speaker.textContent = (c.advisories || 0) + ' advisories, ' +
-        (c.resolutions || 0) + ' steering. ' +
-        ((c.resolutions || 0) > 0 ? 'Steering is required.' : 'No steering is required.');
-    }
+    announce((c.advisories || 0) + ' advisories, ' +
+      (c.resolutions || 0) + ' steering. ' +
+      ((c.resolutions || 0) > 0 ? 'Steering is required.' : 'No steering is required.'));
   }
 
   function poll() {
@@ -278,6 +279,9 @@ function renderControlPlaneViewHtml() {
       return r.json();
     }).then(apply).catch(function () {
       document.getElementById('status').textContent = 'offline';
+      // The last guidance is now stale, so replace it rather than leaving the
+      // live region claiming the airspace is clear.
+      announce('Control-plane data is unavailable. Advisories and steering are unknown.');
     });
   }
 

tests/lib/control-plane-view-ui.test.js

@@ -206,6 +206,43 @@ let passed = 0;
     `a changed poll must announce the new counts, got ${changed.elements.get('announce').textContent}`);
   passed += 1;
 
+  // An outage must not leave the live region holding the last known guidance,
+  // which would read as a current "airspace is clear" after data stopped.
+  const outage = await render([
+    { ok: true, data: populatedView() },
+    { ok: false, data: { ok: false, error: 'snapshot unavailable' } }
+  ]);
+  const beforeOutage = outage.elements.get('announce').textContent;
+  await outage.pollAgain();
+  assert.strictEqual(outage.elements.get('status').textContent, 'offline');
+  assert.ok(outage.elements.get('announce').textContent !== beforeOutage,
+    'a failed poll must not leave the previous guidance in the live region');
+  assert.ok(/unavailable/i.test(outage.elements.get('announce').textContent)
+    && /unknown/i.test(outage.elements.get('announce').textContent),
+    `an outage must say the counts are unknown, got ${outage.elements.get('announce').textContent}`);
+  passed += 1;
+
+  // A repeated failure stays silent, but recovering online must speak again.
+  const writesAfterOutage = outage.writesTo('announce');
+  await outage.pollAgain();
+  assert.strictEqual(outage.writesTo('announce'), writesAfterOutage,
+    'a repeated failure must not re-announce the same outage');
+  passed += 1;
+
+  const recovered = await render([
+    { ok: true, data: populatedView() },
+    { ok: false, data: { ok: false, error: 'snapshot unavailable' } },
+    { ok: true, data: populatedView({ counts: { tasks: 3, lanes: 1, agents: 2, advisories: 1, resolutions: 1 } }) }
+  ]);
+  await recovered.pollAgain();
+  await recovered.pollAgain();
+  assert.ok(recovered.elements.get('status').textContent.includes('3 tasks'),
+    'a recovered poll must restore the live status');
+  assert.ok(recovered.elements.get('announce').textContent.includes('1 advisories')
+    && recovered.elements.get('announce').textContent.includes('Steering is required.'),
+    `a recovered poll must announce the restored counts, got ${recovered.elements.get('announce').textContent}`);
+  passed += 1;
+
   console.log(`Results: Passed: ${passed}, Failed: 0`);
 })().catch(error => {
   console.error(error.message);