Add AI weekly and monthly summaries with archive UI and backup support

assets/css/app.css

@@ -1150,6 +1150,59 @@ input[type="range"] {
     gap: 0.75rem;
 }
 
+.archive-summary-section {
+    display: grid;
+    gap: 0.9rem;
+    margin-bottom: 1.2rem;
+}
+
+.archive-summary-grid {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
+    gap: 0.85rem;
+}
+
+.archive-summary-card {
+    display: grid;
+    gap: 0.7rem;
+    padding: 1rem 1.05rem;
+    border-radius: 18px;
+    background: rgba(255, 255, 255, 0.08);
+    border: 1px solid rgba(255, 255, 255, 0.08);
+}
+
+.archive-summary-card__head {
+    display: flex;
+    justify-content: space-between;
+    gap: 0.8rem;
+    align-items: flex-start;
+}
+
+.archive-summary-card__head strong {
+    display: block;
+    margin-top: 0.35rem;
+}
+
+.summary-badge {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    min-width: 2.15rem;
+    min-height: 1.55rem;
+    padding: 0.15rem 0.5rem;
+    border-radius: 999px;
+    background: rgba(139, 228, 255, 0.16);
+    border: 1px solid rgba(139, 228, 255, 0.24);
+    color: var(--text);
+    font-size: 0.75rem;
+    font-weight: 700;
+    letter-spacing: 0.06em;
+}
+
+.chart-chip--muted {
+    opacity: 0.82;
+}
+
 .archive-item {
     display: flex;
     justify-content: space-between;
@@ -1185,6 +1238,15 @@ input[type="range"] {
     flex-wrap: wrap;
 }
 
+.archive-item__actions--stack {
+    justify-content: flex-start;
+    align-items: stretch;
+}
+
+.archive-item__actions--stack form {
+    margin: 0;
+}
+
 .archive-action {
     min-height: 2.4rem;
     padding-inline: 0.85rem;
@@ -1242,6 +1304,10 @@ input[type="range"] {
     background: rgba(255, 255, 255, 0.08);
 }
 
+.note-box--summary p {
+    white-space: pre-wrap;
+}
+
 .note-box h4 {
     margin: 0 0 0.55rem;
 }
@@ -1536,6 +1602,10 @@ input[type="range"] {
         align-items: flex-start;
     }
 
+    .archive-summary-grid {
+        grid-template-columns: 1fr;
+    }
+
     .calendar-detail {
         flex-direction: column;
         align-items: flex-start;