Add persistent per-screen brightness, standby and clock settings

screen_manager/app/static/style.css

@@ -563,3 +563,56 @@ textarea {
     margin-left: 0;
   }
 }
+
+.screen-settings {
+  margin: 28px 0 20px;
+  border-top: 1px solid var(--line);
+  padding-top: 20px;
+}
+.screen-settings summary {
+  cursor: pointer;
+  font-size: 18px;
+  font-weight: 700;
+}
+.settings-grid {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  gap: 16px 28px;
+  margin: 20px 0;
+}
+.setting {
+  padding: 14px;
+  border: 1px solid var(--line);
+  border-radius: 12px;
+}
+.setting output {
+  display: block;
+  color: var(--muted);
+  font-size: 13px;
+}
+.setting input[type="range"] {
+  padding: 0;
+  accent-color: var(--accent);
+  min-height: 32px;
+}
+.setting-check {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+.setting-check input {
+  width: 22px;
+  height: 22px;
+  flex-shrink: 0;
+  margin: 0;
+  accent-color: var(--accent);
+}
+.setting-check output {
+  display: none;
+}
+@media (max-width: 640px) {
+  .settings-grid {
+    grid-template-columns: 1fr;
+  }
+}