feat(nostr-feed): Add inline reply forms for comments

- Add inline reply form that appears below the comment being replied to
- Pass replyingToId and isSubmittingReply props through comment tree
- Add cancel-reply and submit-reply events for inline form handling
- Top composer now only shows for new top-level comments
- Better UX: no need to scroll to top to reply to nested comments

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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

@@ -4,9 +4,9 @@
  * Displays a single comment with vote controls and nested replies
  */
 
-import { computed } from 'vue'
+import { computed, ref } from 'vue'
 import { formatDistanceToNow } from 'date-fns'
-import { ChevronUp, ChevronDown, Reply, Flag, MoreHorizontal } from 'lucide-vue-next'
+import { ChevronUp, ChevronDown, Reply, Flag, MoreHorizontal, Send, X } from 'lucide-vue-next'
 import VoteControls from './VoteControls.vue'
 import type { SubmissionComment as CommentType } from '../types/submission'
 
@@ -17,18 +17,49 @@ interface Props {
   getDisplayName: (pubkey: string) => string
   isAuthenticated: boolean
   currentUserPubkey?: string | null
+  replyingToId?: string | null
+  isSubmittingReply?: boolean
 }
 
 interface Emits {
   (e: 'toggle-collapse', commentId: string): void
   (e: 'reply', comment: CommentType): void
+  (e: 'cancel-reply'): void
+  (e: 'submit-reply', commentId: string, text: string): void
   (e: 'upvote', comment: CommentType): void
   (e: 'downvote', comment: CommentType): void
 }
 
-const props = defineProps<Props>()
+const props = withDefaults(defineProps<Props>(), {
+  replyingToId: null,
+  isSubmittingReply: false
+})
 const emit = defineEmits<Emits>()
 
+// Local reply text
+const replyText = ref('')
+
+// Is this comment being replied to
+const isBeingRepliedTo = computed(() => props.replyingToId === props.comment.id)
+
+// Handle reply click
+function onReplyClick() {
+  emit('reply', props.comment)
+}
+
+// Submit the reply
+function submitReply() {
+  if (!replyText.value.trim()) return
+  emit('submit-reply', props.comment.id, replyText.value.trim())
+  replyText.value = ''
+}
+
+// Cancel reply
+function cancelReply() {
+  replyText.value = ''
+  emit('cancel-reply')
+}
+
 // Is this comment collapsed
 const isCollapsed = computed(() => props.collapsedComments.has(props.comment.id))
 
@@ -168,7 +199,8 @@ const isOwnComment = computed(() =>
           <!-- Reply -->
           <button
             class="flex items-center gap-1 px-2 py-1 text-xs text-muted-foreground hover:text-foreground hover:bg-accent rounded transition-colors"
-            @click="emit('reply', comment)"
+            :disabled="!isAuthenticated"
+            @click="onReplyClick"
           >
             <Reply class="h-3 w-3" />
             <span>reply</span>
@@ -191,6 +223,35 @@ const isOwnComment = computed(() =>
           </button>
         </div>
 
+        <!-- Inline reply form -->
+        <div v-if="isBeingRepliedTo" class="mt-2 pl-5">
+          <div class="border rounded-lg bg-background p-2">
+            <textarea
+              v-model="replyText"
+              placeholder="Write a reply..."
+              rows="3"
+              class="w-full px-2 py-1.5 text-sm bg-transparent resize-none focus:outline-none"
+              :disabled="isSubmittingReply"
+            />
+            <div class="flex items-center justify-end gap-2 mt-1">
+              <button
+                class="px-3 py-1 text-xs text-muted-foreground hover:text-foreground transition-colors"
+                @click="cancelReply"
+              >
+                Cancel
+              </button>
+              <button
+                class="flex items-center gap-1 px-3 py-1 text-xs bg-primary text-primary-foreground rounded hover:bg-primary/90 transition-colors disabled:opacity-50"
+                :disabled="!replyText.trim() || isSubmittingReply"
+                @click="submitReply"
+              >
+                <Send class="h-3 w-3" />
+                Reply
+              </button>
+            </div>
+          </div>
+        </div>
+
         <!-- Nested replies -->
         <div v-if="hasReplies" class="mt-1">
           <SubmissionComment
@@ -202,8 +263,12 @@ const isOwnComment = computed(() =>
             :get-display-name="getDisplayName"
             :is-authenticated="isAuthenticated"
             :current-user-pubkey="currentUserPubkey"
+            :replying-to-id="replyingToId"
+            :is-submitting-reply="isSubmittingReply"
             @toggle-collapse="emit('toggle-collapse', $event)"
             @reply="emit('reply', $event)"
+            @cancel-reply="emit('cancel-reply')"
+            @submit-reply="(commentId, text) => emit('submit-reply', commentId, text)"
             @upvote="emit('upvote', $event)"
             @downvote="emit('downvote', $event)"
           />

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

@@ -169,14 +169,20 @@ function onShare() {
   // TODO: Show toast
 }
 
-// Handle comment reply
+// Computed for passing to comment components
+const replyingToId = computed(() => replyingTo.value?.id || null)
+
+// Handle comment reply - for inline replies to comments
 function startReply(comment?: SubmissionCommentType) {
   if (comment) {
+    // Replying to a comment - show inline form (handled by SubmissionComment)
     replyingTo.value = { id: comment.id, author: getDisplayName(comment.pubkey) }
+    showComposer.value = false // Hide top composer
   } else {
+    // Top-level comment - show top composer
     replyingTo.value = null
-  }
     showComposer.value = true
+  }
   commentText.value = ''
 }
 
@@ -186,6 +192,7 @@ function cancelReply() {
   commentText.value = ''
 }
 
+// Submit top-level comment (from top composer)
 async function submitComment() {
   if (!commentText.value.trim() || !isAuthenticated.value || !submissionService) return
 
@@ -196,7 +203,7 @@ async function submitComment() {
     await submissionService.createComment(
       props.submissionId,
       commentText.value.trim(),
-      replyingTo.value?.id
+      null // Top-level comment
     )
     cancelReply()
   } catch (err: any) {
@@ -207,6 +214,28 @@ async function submitComment() {
   }
 }
 
+// Submit inline reply (from SubmissionComment's inline form)
+async function submitReply(commentId: string, text: string) {
+  if (!text.trim() || !isAuthenticated.value || !submissionService) return
+
+  isSubmittingComment.value = true
+  commentError.value = null
+
+  try {
+    await submissionService.createComment(
+      props.submissionId,
+      text.trim(),
+      commentId
+    )
+    cancelReply()
+  } catch (err: any) {
+    console.error('Failed to submit reply:', err)
+    commentError.value = err.message || 'Failed to post reply'
+  } finally {
+    isSubmittingComment.value = false
+  }
+}
+
 // Toggle comment collapse
 function toggleCollapse(commentId: string) {
   if (collapsedComments.value.has(commentId)) {
@@ -429,17 +458,12 @@ function goBack() {
         </div>
       </article>
 
-      <!-- Comment composer -->
+      <!-- Top-level comment composer (only for new comments, not replies) -->
-      <div v-if="showComposer || isAuthenticated" class="p-4 border-b">
+      <div v-if="isAuthenticated && !replyingTo" class="p-4 border-b">
-        <div v-if="replyingTo" class="text-xs text-muted-foreground mb-2">
-          Replying to {{ replyingTo.author }}
-          <button class="ml-2 text-primary hover:underline" @click="cancelReply">Cancel</button>
-        </div>
         <div class="flex gap-2">
           <textarea
             v-model="commentText"
-            :placeholder="isAuthenticated ? 'Write a comment...' : 'Login to comment'"
+            placeholder="Write a comment..."
-            :disabled="!isAuthenticated"
             rows="3"
             class="flex-1 px-3 py-2 text-sm border rounded-lg bg-background resize-none focus:outline-none focus:ring-2 focus:ring-primary"
           />
@@ -451,7 +475,7 @@ function goBack() {
         <div class="flex justify-end mt-2">
           <Button
             size="sm"
-            :disabled="!commentText.trim() || isSubmittingComment || !isAuthenticated"
+            :disabled="!commentText.trim() || isSubmittingComment"
             @click="submitComment"
           >
             <Loader2 v-if="isSubmittingComment" class="h-4 w-4 animate-spin mr-2" />
@@ -490,8 +514,12 @@ function goBack() {
             :get-display-name="getDisplayName"
             :is-authenticated="isAuthenticated"
             :current-user-pubkey="currentUserPubkey"
+            :replying-to-id="replyingToId"
+            :is-submitting-reply="isSubmittingComment"
             @toggle-collapse="toggleCollapse"
             @reply="startReply"
+            @cancel-reply="cancelReply"
+            @submit-reply="submitReply"
             @upvote="onCommentUpvote"
             @downvote="onCommentDownvote"
           />