fix(tests): use bar groups for incident selection, add warm-up to BVT

- selectIncidentByBarIndex/deselectIncidentByBar: use
  incidentsChartBarsGroups() (one element per incident) instead of
  incidentsChartBarsVisiblePaths() (flattened paths). Fixes incorrect
  incident selection/deselection with multi-severity incidents.
- findIncidentWithAlert: count bar groups instead of flattened paths
- deselectIncidentByBar: accept index parameter to deselect the
  correct incident instead of always clicking the first bar
- 01.incidents.cy.ts: add warmUpForPlugin() to before() hook —
  same plugin loading race fix as reg/02-05

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Claude Agent

web/cypress/e2e/incidents/01.incidents.cy.ts

@@ -27,6 +27,7 @@ const MP = {
 describe('BVT: Incidents - UI', { tags: ['@smoke', '@incidents'] }, () => {
   before(() => {
     cy.beforeBlockCOO(MCP, MP, { dashboards: false, troubleshootingPanel: false });
+    incidentsPage.warmUpForPlugin();
     cy.mockIncidentFixture(
       'incident-scenarios/1-single-incident-firing-critical-and-warning-alerts.yaml',
     );

web/cypress/views/incidents-page.ts

@@ -399,42 +399,37 @@ export const incidentsPage = {
   },
 
   /**
-   * Selects an incident from the chart by clicking on a bar at the specified index.
-   * BUG: Problems with multi-severity incidents (multiple paths in a single incident bar)
+   * Selects an incident from the chart by clicking on a bar group at the
+   * specified index. Uses bar groups (one per incident) instead of flattened
+   * paths to correctly handle multi-severity incidents.
    *
    * @param index - Zero-based index of the incident bar to click (default: 0)
    * @returns Promise that resolves when the incidents table is visible
    */
   selectIncidentByBarIndex: (index = 0) => {
-    if (!_quietSearch)
-      cy.log(`incidentsPage.selectIncidentByBarIndex: ${index} (clicking visible path elements)`);
+    if (!_quietSearch) cy.log(`incidentsPage.selectIncidentByBarIndex: ${index}`);
 
     return incidentsPage.elements
-      .incidentsChartBarsVisiblePaths()
+      .incidentsChartBarsGroups()
       .should('have.length.greaterThan', index)
-      .then(($paths) => {
-        if (index >= $paths.length) {
-          throw new Error(`Index ${index} exceeds available paths (${$paths.length})`);
-        }
-
-        return cy.wrap($paths.eq(index), _qLog()).click({ force: true, ..._qLog() });
-      })
+      .eq(index)
+      .find('path[role="presentation"]')
+      .first()
+      .click({ force: true, ..._qLog() })
       .then(() => {
         cy.wait(2000, _qLog());
         return incidentsPage.elements.incidentsTable().scrollIntoView().should('exist');
       });
   },
 
-  deselectIncidentByBar: () => {
+  deselectIncidentByBar: (index = 0) => {
     if (!_quietSearch) cy.log('incidentsPage.deselectIncidentByBar');
     return incidentsPage.elements
-      .incidentsChartBarsVisiblePaths()
-      .then(($paths) => {
-        if ($paths.length === 0) {
-          throw new Error('No paths found in incidents chart');
-        }
-        return cy.wrap($paths.eq(0), _qLog()).click({ force: true, ..._qLog() });
-      })
+      .incidentsChartBarsGroups()
+      .eq(index)
+      .find('path[role="presentation"]')
+      .first()
+      .click({ force: true, ..._qLog() })
       .then(() => {
         return incidentsPage.elements.incidentsTable().should('not.exist');
       });
@@ -653,8 +648,10 @@ export const incidentsPage = {
 
   prepareIncidentsPageForSearch: () => {
     if (!_quietSearch) cy.log('incidentsPage.prepareIncidentsPageForSearch: Setting up page...');
-    // Force a hard page reload to release browser DOM memory from previous search iterations.
-    cy.reload({ log: false });
+    // Use SPA navigation instead of cy.reload() — the Incidents component is a
+    // dynamic plugin chunk, and cy.reload() causes the Console to re-resolve all
+    // plugins from scratch, which silently fails in headless CI (blank page).
+    // OOM is handled by _quietSearch suppressing DOM snapshots, not by reload.
     incidentsPage.goTo();
     incidentsPage.setDays(incidentsPage.SEARCH_CONFIG.DEFAULT_DAYS);
     incidentsPage.elements.incidentsChartContainer().should('be.visible');
@@ -821,7 +818,7 @@ export const incidentsPage = {
         if (found) {
           return cy.wrap(true, _qLog());
         }
-        incidentsPage.deselectIncidentByBar();
+        incidentsPage.deselectIncidentByBar(currentIndex);
         cy.wait(500, _qLog());
         return searchNextIncidentBar(currentIndex + 1);
       });
@@ -859,16 +856,19 @@ export const incidentsPage = {
 
     incidentsPage.prepareIncidentsPageForSearch();
 
-    return incidentsPage.elements
-      .incidentsChartBarsVisiblePaths()
-      .then(($paths) => {
-        const totalPaths = $paths.length;
-        if (totalPaths === 0) {
-          cy.log('No visible incident bar paths found in chart');
+    // Check for bar groups without asserting existence — an empty chart is
+    // valid (e.g. when mocking empty incidents or before detection fires).
+    return cy
+      .get('body', _qLog())
+      .then(($body) => {
+        const barSelector = 'g[role="presentation"][data-test*="incidents-chart-bar-"]';
+        const totalIncidents = $body.find(barSelector).length;
+        if (totalIncidents === 0) {
+          if (!_quietSearch) cy.log('No incident bar groups found in chart');
           return cy.wrap(false, { log: false });
         }
 
-        return incidentsPage.traverseAllIncidentsBars(alertName, totalPaths);
+        return incidentsPage.traverseAllIncidentsBars(alertName, totalIncidents);
       })
       .then((found: boolean) => {
         if (found) {