feat: Add UI optional UI locking when microphone is hot (#2484)

src/scss/locked.scss

@@ -0,0 +1,8 @@
+// Shared styling for components that reflect a `locked` host attribute (set by
+// Lit when the consumer-facing `locked` property is true). Dims the host and
+// disables pointer interaction without removing it from layout, so the element
+// stays in place during mic mute/unmute transitions.
+:host([locked]) {
+  opacity: 0.4;
+  pointer-events: none;
+}

src/scss/next-previous-control.scss

@@ -1,4 +1,5 @@
 @use './button.scss';
+@use 'locked.scss';
 
 :host {
   --advanced-camera-card-next-prev-size: 48px;

src/scss/thumbnail-carousel.scss

@@ -1,4 +1,5 @@
 @use 'const.scss';
+@use 'locked.scss';
 
 :host {
   display: block;

src/scss/timeline-core.scss

@@ -1,6 +1,7 @@
 @use 'vis-timeline/dist/vis-timeline-graph2d.css';
 @use 'drawer';
 @use 'const.scss';
+@use 'locked.scss';
 
 :host {
   width: 100%;