Add DM inbox with NIP-04/NIP-17 support and soft delete

Features:
- Full DM inbox UI with conversation list and message view
- Support for both NIP-04 (kind 4) and NIP-17 (kind 14/1059) encryption
- Progressive message decryption with background loading
- Soft delete using kind 30078 Application Specific Data events
- Message selection UI with delete selected/delete all
- Undelete all functionality per conversation
- Jump to newest button with new message counter
- Conversation filtering (all / follows only)
- Per-conversation relay and encryption settings
- New messages indicator on sidebar (clears when inbox viewed)
- Follow indicator on conversation items

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

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

src/components/Inbox/ConversationItem.tsx

@@ -0,0 +1,81 @@
+import UserAvatar from '@/components/UserAvatar'
+import { formatTimestamp } from '@/lib/timestamp'
+import { cn } from '@/lib/utils'
+import client from '@/services/client.service'
+import { TConversation, TProfile } from '@/types'
+import { Lock, Users } from 'lucide-react'
+import { useEffect, useState } from 'react'
+
+interface ConversationItemProps {
+  conversation: TConversation
+  isActive: boolean
+  isFollowing: boolean
+  onClick: () => void
+}
+
+export default function ConversationItem({
+  conversation,
+  isActive,
+  isFollowing,
+  onClick
+}: ConversationItemProps) {
+  const [profile, setProfile] = useState<TProfile | null>(null)
+
+  useEffect(() => {
+    const fetchProfileData = async () => {
+      try {
+        const profileData = await client.fetchProfile(conversation.partnerPubkey)
+        if (profileData) {
+          setProfile(profileData)
+        }
+      } catch (error) {
+        console.error('Failed to fetch profile:', error)
+      }
+    }
+    fetchProfileData()
+  }, [conversation.partnerPubkey])
+
+  const displayName = profile?.username || conversation.partnerPubkey.slice(0, 8) + '...'
+  const formattedTime = formatTimestamp(conversation.lastMessageAt)
+
+  return (
+    <button
+      onClick={onClick}
+      className={cn(
+        'w-full flex items-start gap-3 p-3 hover:bg-accent/50 transition-colors text-left',
+        isActive && 'bg-accent'
+      )}
+    >
+      <UserAvatar userId={conversation.partnerPubkey} className="size-10 flex-shrink-0" />
+
+      <div className="flex-1 min-w-0">
+        <div className="flex items-center justify-between gap-2">
+          <div className="flex items-center gap-1.5 min-w-0">
+            <span className="font-medium text-sm truncate">{displayName}</span>
+            {isFollowing && (
+              <span className="text-xs text-primary flex-shrink-0" title="Following">
+                <Users className="size-3" />
+              </span>
+            )}
+          </div>
+          <span className="text-xs text-muted-foreground flex-shrink-0">{formattedTime}</span>
+        </div>
+
+        <div className="flex items-center gap-1.5 mt-0.5">
+          {conversation.preferredEncryption === 'nip17' && (
+            <span title="NIP-17 encrypted">
+              <Lock className="size-3 text-green-500 flex-shrink-0" />
+            </span>
+          )}
+          <p className="text-sm text-muted-foreground truncate">{conversation.lastMessagePreview}</p>
+        </div>
+
+        {conversation.unreadCount > 0 && (
+          <span className="inline-flex items-center justify-center size-5 text-xs rounded-full bg-primary text-primary-foreground mt-1">
+            {conversation.unreadCount}
+          </span>
+        )}
+      </div>
+    </button>
+  )
+}