style(comments): tighten aside panel spacing and widen it

- Widen the comments/aside panel from 350 to 420 (~20% wider)
- Remove double padding around the panel: AppShell.Aside p="md"->"sm"
  and inner Box p="md"->p={0}; reduce header-to-tabs gap mb="md"->"sm"
- Reduce empty space below the add-comment input (paddingBottom 25->10),
  align the avatar with the input box (marginTop 10->2) and re-anchor the
  send button (bottom 30->15)
- Pull the timestamp closer to the nickname via tighter line-height
  (lh 1.2 on the name, 1.1 on the "… ago" text)

apps/client/src/features/comment/components/comment-list-item.tsx

@@ -126,7 +126,7 @@ function CommentListItem({
 
         <div style={{ flex: 1 }}>
           <Group justify="space-between" wrap="nowrap">
-            <Text size="xs" fw={500} lineClamp={1}>
+            <Text size="xs" fw={500} lineClamp={1} lh={1.2}>
               {comment.creator.name}
             </Text>
 
@@ -155,7 +155,7 @@ function CommentListItem({
           </Group>
 
           <Group gap="xs">
-            <Text size="xs" fw={500} c="dimmed">
+            <Text size="xs" fw={500} c="dimmed" lh={1.1}>
               {createdAtAgo}
             </Text>
           </Group>

apps/client/src/features/comment/components/comment-list-with-tabs.tsx

@@ -365,7 +365,7 @@ const PageCommentInput = ({ onSave, isLoading }) => {
         flex: "0 0 auto",
         borderTop: "1px solid var(--mantine-color-default-border)",
         paddingTop: "var(--mantine-spacing-sm)",
-        paddingBottom: 25,
+        paddingBottom: 10,
         position: "relative",
       }}
     >
@@ -374,7 +374,7 @@ const PageCommentInput = ({ onSave, isLoading }) => {
           size="sm"
           avatarUrl={currentUser?.user?.avatarUrl}
           name={currentUser?.user?.name}
-          style={{ flexShrink: 0, marginTop: 10 }}
+          style={{ flexShrink: 0, marginTop: 2 }}
         />
         <div style={{ flex: 1, minWidth: 0 }}>
           <CommentEditor
@@ -396,7 +396,7 @@ const PageCommentInput = ({ onSave, isLoading }) => {
           onClick={handleSave}
           onMouseDown={(e) => e.preventDefault()}
           loading={isLoading}
-          style={{ position: "absolute", right: 8, bottom: 30 }}
+          style={{ position: "absolute", right: 8, bottom: 15 }}
         >
           <IconArrowUp size={16} />
         </ActionIcon>