feat(sns): add contact timeline dialog components

src/components/Sns/contactSnsTimeline.ts

@@ -0,0 +1,26 @@
+export interface ContactSnsTimelineTarget {
+  username: string
+  displayName: string
+  avatarUrl?: string
+}
+
+export interface ContactSnsRankItem {
+  name: string
+  count: number
+  latestTime: number
+}
+
+export type ContactSnsRankMode = 'likes' | 'comments'
+
+export const isSingleContactSession = (sessionId: string): boolean => {
+  const normalized = String(sessionId || '').trim()
+  if (!normalized) return false
+  if (normalized.includes('@chatroom')) return false
+  if (normalized.startsWith('gh_')) return false
+  return true
+}
+
+export const getAvatarLetter = (name: string): string => {
+  if (!name) return '?'
+  return [...name][0] || '?'
+}