Add scanner utility, modal, and stock scan page implementation

src/styles/app.css

@@ -1099,6 +1099,109 @@ button.legend-card:focus-visible {
   object-fit: cover;
 }
 
+.scan-hero {
+  background:
+    radial-gradient(circle at 15% 20%, rgba(80, 180, 140, 0.18), transparent 28rem),
+    linear-gradient(145deg, rgba(255, 255, 255, 0.96), rgba(245, 250, 255, 0.92));
+}
+
+.scan-mode-grid {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  gap: 0.8rem;
+}
+
+.scan-mode-card {
+  display: grid;
+  gap: 0.25rem;
+  min-height: 6rem;
+  padding: 1rem;
+  text-align: left;
+  color: inherit;
+  background: rgba(255, 255, 255, 0.74);
+  border: 1px solid var(--lonc-border);
+  border-radius: 1rem;
+  transition:
+    transform 160ms ease,
+    box-shadow 160ms ease,
+    border-color 160ms ease,
+    background-color 160ms ease;
+}
+
+.scan-mode-card:hover {
+  transform: translateY(-1px);
+  box-shadow: 0 12px 24px rgba(24, 42, 79, 0.08);
+}
+
+.scan-mode-card-active {
+  border-color: rgba(31, 75, 153, 0.42);
+  background: rgba(31, 75, 153, 0.1);
+  box-shadow: inset 0 0 0 1px rgba(31, 75, 153, 0.18);
+}
+
+.scan-candidate-list {
+  max-height: 24rem;
+  overflow-y: auto;
+}
+
+.scan-modal-mode-list {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.45rem;
+}
+
+.scan-modal-mode-btn {
+  border-radius: 999px;
+}
+
+.scan-modal-mode-btn-active {
+  color: #fff;
+  background: var(--lonc-primary);
+  border-color: var(--lonc-primary);
+}
+
+.scan-label-mode-list {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.45rem;
+}
+
+.scan-label-mode-btn {
+  border-radius: 999px;
+}
+
+.scan-label-mode-btn-active {
+  color: #fff;
+  background: var(--lonc-primary-dark);
+  border-color: var(--lonc-primary-dark);
+}
+
+.scan-result-card {
+  padding: 1.25rem;
+  border-radius: 1.25rem;
+  border: 1px solid var(--lonc-border);
+  background:
+    linear-gradient(135deg, rgba(235, 243, 255, 0.78), rgba(255, 255, 255, 0.92));
+}
+
+.empty-state-inline {
+  display: grid;
+  min-height: 12rem;
+  place-items: center;
+  padding: 2rem;
+  color: var(--lonc-muted);
+  text-align: center;
+  border: 1px dashed rgba(31, 75, 153, 0.22);
+  border-radius: 1.25rem;
+  background: rgba(255, 255, 255, 0.58);
+}
+
+@media (max-width: 575.98px) {
+  .scan-mode-grid {
+    grid-template-columns: 1fr;
+  }
+}
+
 @media (max-width: 991.98px) {
   .navbar {
     backdrop-filter: blur(10px);