fix(nostr-feed): Fix comment loading and deduplication

- Add subscribeToSubmission() to fetch submission + comments by ID
- Fix isComment check order - check before parseSubmission (which fails for comments)
- Update comment count on submission when comments are added
- Add duplicate comment detection to prevent double-display
- Update useSubmission composable to auto-subscribe on mount

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

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

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

@@ -4,7 +4,7 @@
  * Displays complete submission content and threaded comments
  */
 
-import { ref, computed, onMounted, watch } from 'vue'
+import { ref, computed } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { formatDistanceToNow } from 'date-fns'
 import {
@@ -26,7 +26,7 @@ import { Badge } from '@/components/ui/badge'
 import { Button } from '@/components/ui/button'
 import VoteControls from './VoteControls.vue'
 import SubmissionCommentComponent from './SubmissionComment.vue'
-import { useSubmission, useSubmissions } from '../composables/useSubmissions'
+import { useSubmission } from '../composables/useSubmissions'
 import { tryInjectService, SERVICE_TOKENS } from '@/core/di-container'
 import type { ProfileService } from '../services/ProfileService'
 import type { SubmissionService } from '../services/SubmissionService'
@@ -54,11 +54,8 @@ const profileService = tryInjectService<ProfileService>(SERVICE_TOKENS.PROFILE_S
 const authService = tryInjectService<any>(SERVICE_TOKENS.AUTH_SERVICE)
 const submissionService = tryInjectService<SubmissionService>(SERVICE_TOKENS.SUBMISSION_SERVICE)
 
-// Use submission composable
-const { submission, comments, upvote, downvote } = useSubmission(props.submissionId)
-
-// Subscribe to fetch the submission if not already loaded
-const { subscribe, isLoading, error } = useSubmissions({ autoSubscribe: false })
+// Use submission composable - handles subscription automatically
+const { submission, comments, upvote, downvote, isLoading, error } = useSubmission(props.submissionId)
 
 // Comment composer state
 const showComposer = ref(false)
@@ -215,13 +212,6 @@ function countReplies(comment: SubmissionCommentType): number {
 function goBack() {
   router.back()
 }
-
-// Subscribe on mount if submission not loaded
-onMounted(() => {
-  if (!submission.value) {
-    subscribe({ limit: 50 })
-  }
-})
 </script>
 
 <template>

src/modules/nostr-feed/composables/useSubmissions.ts

@@ -289,9 +289,27 @@ export function useSubmissions(options: UseSubmissionsOptions = {}): UseSubmissi
 export function useSubmission(submissionId: string) {
   const submissionService = tryInjectService<SubmissionService>(SERVICE_TOKENS.SUBMISSION_SERVICE)
 
+  const isLoading = ref(false)
+  const error = ref<string | null>(null)
+
   const submission = computed(() => submissionService?.getSubmission(submissionId))
   const comments = computed(() => submissionService?.getThreadedComments(submissionId) ?? [])
 
+  async function subscribe(): Promise<void> {
+    if (!submissionService) return
+
+    isLoading.value = true
+    error.value = null
+
+    try {
+      await submissionService.subscribeToSubmission(submissionId)
+    } catch (err: any) {
+      error.value = err.message || 'Failed to load submission'
+    } finally {
+      isLoading.value = false
+    }
+  }
+
   async function upvote(): Promise<void> {
     await submissionService?.upvote(submissionId)
   }
@@ -300,9 +318,17 @@ export function useSubmission(submissionId: string) {
     await submissionService?.downvote(submissionId)
   }
 
+  // Subscribe on mount
+  onMounted(() => {
+    subscribe()
+  })
+
   return {
     submission,
     comments,
+    isLoading: computed(() => isLoading.value || submissionService?.isLoading.value || false),
+    error: computed(() => error.value || submissionService?.error.value || null),
+    subscribe,
     upvote,
     downvote
   }

src/modules/nostr-feed/services/SubmissionService.ts

@@ -183,6 +183,78 @@ export class SubmissionService extends BaseService {
     }
   }
 
+  /**
+   * Subscribe to a specific submission and its comments
+   */
+  async subscribeToSubmission(submissionId: string): Promise<void> {
+    this._isLoading.value = true
+    this._error.value = null
+
+    try {
+      if (!this.relayHub?.isConnected) {
+        await this.relayHub?.connect()
+      }
+
+      const subscriptionId = `submission-${submissionId}-${Date.now()}`
+
+      // Build filters for the submission and its comments
+      const filters: Filter[] = [
+        // The submission itself
+        {
+          kinds: [SUBMISSION_KINDS.SUBMISSION],
+          ids: [submissionId]
+        },
+        // Comments referencing this submission (via 'e' tag - parent reference)
+        {
+          kinds: [SUBMISSION_KINDS.SUBMISSION],
+          '#e': [submissionId]
+        },
+        // Comments referencing this submission (via 'E' tag - root reference)
+        {
+          kinds: [SUBMISSION_KINDS.SUBMISSION],
+          '#E': [submissionId]
+        },
+        // Reactions on the submission and comments
+        {
+          kinds: [SUBMISSION_KINDS.REACTION],
+          '#e': [submissionId]
+        }
+      ]
+
+      this.debug('Subscribing to submission with filters:', filters)
+
+      const unsubscribe = this.relayHub.subscribe({
+        id: subscriptionId,
+        filters,
+        onEvent: (event: NostrEvent) => this.handleEvent(event),
+        onEose: () => {
+          this.debug('End of stored events for submission')
+          this._isLoading.value = false
+        },
+        onClose: () => {
+          this.debug('Submission subscription closed')
+        }
+      })
+
+      // Store for cleanup (don't overwrite main subscription)
+      // For now, we'll manage this separately
+      this.currentSubscription = subscriptionId
+      this.currentUnsubscribe = unsubscribe
+
+      // Timeout fallback
+      setTimeout(() => {
+        if (this._isLoading.value && this.currentSubscription === subscriptionId) {
+          this._isLoading.value = false
+        }
+      }, 10000)
+
+    } catch (err) {
+      this._error.value = err instanceof Error ? err.message : 'Failed to subscribe to submission'
+      this._isLoading.value = false
+      throw err
+    }
+  }
+
   /**
    * Build Nostr filters from feed configuration
    */
@@ -274,6 +346,12 @@ export class SubmissionService extends BaseService {
     }
     this.seenEventIds.add(event.id)
 
+    // Check if this is a top-level submission or a comment
+    if (this.isComment(event)) {
+      this.handleCommentEvent(event)
+      return
+    }
+
     // Parse the submission
     const submission = this.parseSubmission(event)
     if (!submission) {
@@ -281,12 +359,6 @@ export class SubmissionService extends BaseService {
       return
     }
 
-    // Check if this is a top-level submission or a comment
-    if (this.isComment(event)) {
-      this.handleCommentEvent(event)
-      return
-    }
-
     // Create full submission with metadata
     const submissionWithMeta = this.enrichSubmission(submission)
     this._submissions.set(submission.id, submissionWithMeta)
@@ -329,6 +401,12 @@ export class SubmissionService extends BaseService {
 
     const rootId = rootTag[1]
 
+    // Check for duplicate comment
+    const existingComments = this._comments.get(rootId)
+    if (existingComments?.some(c => c.id === event.id)) {
+      return
+    }
+
     // Parse as comment
     const comment: SubmissionComment = {
       id: event.id,
@@ -347,6 +425,12 @@ export class SubmissionService extends BaseService {
       this._comments.set(rootId, [])
     }
     this._comments.get(rootId)!.push(comment)
+
+    // Update comment count on the submission
+    const submission = this._submissions.get(rootId)
+    if (submission) {
+      submission.commentCount = this._comments.get(rootId)!.length
+    }
   }
 
   /**