style: update padding in page containers for consistency

- Changed padding from 20px to 1rem in multiple Vue components to standardize layout.
- Affected files include channel.vue, index.vue, stream-test.vue, video.vue, cloud.vue, hls-stream.vue, and sample-videos.vue.

src/views/camera/channel.vue

@@ -96,7 +96,7 @@ onMounted(() => {
 
 <style lang="scss" scoped>
 .page-container {
-  padding: 20px;
+  padding: 1rem;
 }
 
 .page-header {

src/views/camera/index.vue

@@ -416,7 +416,7 @@ onMounted(() => {
 
 <style lang="scss" scoped>
 .page-container {
-  padding: 20px;
+  padding: 1rem;
 }
 
 .search-form {

src/views/camera/stream-test.vue

@@ -236,7 +236,7 @@ function goBack() {
 
 <style lang="scss" scoped>
 .page-container {
-  padding: 20px;
+  padding: 1rem;
 }
 
 .page-header {

src/views/camera/video.vue

@@ -38,7 +38,7 @@ function goBack() {
 
 <style lang="scss" scoped>
 .page-container {
-  padding: 20px;
+  padding: 1rem;
 }
 
 .page-header {

src/views/cc/cloud.vue

@@ -401,6 +401,7 @@ async function handleZoomRelease() {
 
 <style lang="scss" scoped>
 .page-container {
+  padding: 1rem;
   min-height: 100vh;
   background-color: var(--bg-page);
 }

src/views/demo/hls-stream.vue

@@ -161,6 +161,7 @@ function onError(error: any) {
 
 <style lang="scss" scoped>
 .page-container {
+  padding: 1rem;
   min-height: 100vh;
   background-color: var(--bg-page);
 }

src/views/demo/sample-videos.vue

@@ -216,6 +216,7 @@ function onError(error: any) {
 
 <style lang="scss" scoped>
 .page-container {
+  padding: 1rem;
   min-height: 100vh;
   background-color: var(--bg-page);
 }