feat: add local agent MCP tools and optional source-grounded AI answers

apps/desktop/src/style.css

@@ -864,6 +864,62 @@ mark[data-match="literal"] {
 #match-legend {
   font-size: 10px;
 }
+.ai-settings {
+  margin-top: 14px;
+}
+.ai-settings summary {
+  cursor: pointer;
+  font-weight: 600;
+}
+.ai-settings label:not(.performance-toggle) {
+  display: block;
+  margin: 10px 0;
+}
+.ai-settings input:not([type="checkbox"]) {
+  width: 100%;
+  margin-top: 4px;
+}
+.ai-panel {
+  margin: 0 20px 12px;
+  font-size: 11px;
+  color: var(--muted);
+}
+.ai-panel summary {
+  cursor: pointer;
+  width: fit-content;
+}
+.ai-panel .eyebrow {
+  margin: 12px 0 6px;
+}
+#ai-source-text,
+#ai-answer {
+  max-height: 150px;
+  overflow: auto;
+  padding: 10px;
+  border: 1px solid var(--line);
+  border-radius: 7px;
+  background: var(--surface);
+  color: var(--ink);
+  font-size: 12px;
+  line-height: 1.6;
+}
+#ai-answer:empty {
+  display: none;
+}
+.ai-actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+  margin-top: 10px;
+}
+.ai-actions input {
+  flex: 1 1 170px;
+  min-width: 0;
+}
+.ai-actions button,
+#ai-citation {
+  font-size: 11px;
+}
 @media (prefers-color-scheme: dark) {
   mark[data-match="literal"] {
     background: #65531e;