Update vertical line styling and indentation in ThreadedPost component

- Changed the class for the vertical line connecting nested replies to improve visual consistency.
- Adjusted the margin calculation for better alignment of nested posts, enhancing the overall layout of threaded discussions.

These updates contribute to a more organized and visually appealing interface within the NostrFeed module.

src/modules/nostr-feed/components/ThreadedPost.vue

@@ -105,8 +105,8 @@ function getRideshareType(post: FeedPost): string {
     <!-- Vertical line connecting to parent (for nested replies) -->
     <div
       v-if="depth > 0"
-      class="absolute left-0 top-0 bottom-0 w-px bg-yellow-500/40"
-      :style="{ marginLeft: `${(depth - 1) * 6 + 3}px` }"
+      class="absolute left-0 top-0 bottom-0 w-px bg-border/40"
+      :style="{ marginLeft: `${depth * 6 + 3}px` }"
     />
 
     <!-- Post container with indentation -->