feat: improve task execution, verification and packaging

Add execution incidents, action bursts and shared Flash history.

Expose verification and Explorer settings with streamed check results.

Support graceful cancellation, recording recovery and bundled UI resources.

Add CI quality checks and clean up comments and documentation.

apps/showcase_ui/src/app/components/agent-stream/agent-stream.component.scss

@@ -3558,5 +3558,162 @@ $stream-row-height: 25px;
   }
 }
 
+/* Checker blocks share the step timeline, marked by a violet left border. */
+.agent-stream-container .stream-logs-content .phase-body .block-item.type-checker {
+  border-left: 2px solid #ddd6fe;
+  padding-left: 12px;
+  margin-left: -14px;
+  font-family: 'Google Sans', 'Google Sans Text', 'Inter', Arial, sans-serif;
 
+  .check-index {
+    flex: 0 0 14px;
+    text-align: right;
+    color: #a1a1aa;
+    font-variant-numeric: tabular-nums;
+    user-select: none;
+  }
 
+  .check-lane {
+    display: flex;
+    flex-direction: column;
+    gap: $uniform-gap;
+    margin-bottom: $uniform-gap;
+
+    .check-header {
+      display: flex;
+      align-items: center;
+      gap: 8px;
+      min-height: 20px;
+      font-size: 12px;
+      line-height: 1.5;
+      letter-spacing: 0.2px;
+      color: #71717a;
+      user-select: none;
+
+      .stream-status-dot {
+        flex: 0 0 auto;
+        width: 8px;
+        height: 8px;
+        border-radius: 50%;
+        display: inline-block;
+        background: #d4d4d8;
+
+        &.streaming {
+          background: #7c3aed;
+          box-shadow: 0 0 0 0 rgba(124, 58, 237, 0.45);
+          animation: pulse-stream-dot 1.8s cubic-bezier(0.4, 0, 0.6, 1) infinite;
+        }
+      }
+
+      .check-title {
+        flex: 0 0 auto;
+        font-weight: 500;
+        color: #52525b;
+      }
+
+      .check-subject {
+        flex: 1 1 auto;
+        min-width: 0;
+        white-space: nowrap;
+        overflow: hidden;
+        text-overflow: ellipsis;
+      }
+
+      .check-status {
+        flex: 0 0 auto;
+        margin-left: auto;
+        font-weight: 500;
+        color: #52525b;
+        white-space: nowrap;
+      }
+    }
+
+    &.tone-passed .check-status { color: #15803d; }
+    &.tone-failed .check-status { color: #b91c1c; }
+    &.tone-inconclusive .check-status { color: #b45309; }
+    &.tone-running .check-status { color: #6d28d9; }
+    &.tone-muted { opacity: 0.6; }
+
+    .check-items {
+      list-style: none;
+      margin: 0;
+      padding: 0 0 0 16px;
+      display: flex;
+      flex-direction: column;
+      gap: 2px;
+
+      .check-item {
+        display: flex;
+        align-items: baseline;
+        gap: 8px;
+        font-size: 12px;
+        line-height: 1.5;
+        color: #3f3f46;
+
+        .check-text {
+          flex: 1 1 auto;
+          min-width: 0;
+          word-break: break-word;
+        }
+
+        .check-method {
+          flex: 0 0 auto;
+          color: #a1a1aa;
+          white-space: nowrap;
+        }
+      }
+    }
+  }
+
+  .check-result {
+    display: flex;
+    flex-direction: column;
+    gap: 4px;
+    margin-top: $uniform-gap;
+    padding-left: 16px;
+
+    .check-verdict {
+      display: flex;
+      align-items: flex-start;
+      gap: 8px;
+      font-size: 12px;
+      line-height: 1.5;
+      color: #52525b;
+
+      .check-index {
+        line-height: 18px;
+      }
+
+      .verdict-icon {
+        flex: 0 0 auto;
+        font-size: 15px;
+        line-height: 18px;
+        color: #a1a1aa;
+      }
+
+      &.passed .verdict-icon { color: #16a34a; }
+      &.failed .verdict-icon { color: #dc2626; }
+      &.inconclusive .verdict-icon { color: #d97706; }
+      &.superseded, &.unchecked { color: #a1a1aa; }
+
+      .verdict-body {
+        flex: 1 1 auto;
+        min-width: 0;
+        word-break: break-word;
+      }
+
+      .verdict-suggestion {
+        display: block;
+        color: #1d4ed8;
+      }
+    }
+
+    .check-note {
+      font-size: 12px;
+      line-height: 1.5;
+      color: #71717a;
+      padding-left: 22px;
+      word-break: break-word;
+    }
+  }
+}