feat(announcements): add admin/user announcement system

Implements announcements end-to-end (admin CRUD + read status, user list + mark read) with OR-of-AND targeting. Also breaks the ent<->service import cycle by moving schema-facing constants/targeting into a new domain package.

frontend/src/types/index.ts

@@ -129,6 +129,81 @@ export interface UpdateSubscriptionRequest {
   is_active?: boolean
 }
 
+// ==================== Announcement Types ====================
+
+export type AnnouncementStatus = 'draft' | 'active' | 'archived'
+
+export type AnnouncementConditionType = 'subscription' | 'balance'
+
+export type AnnouncementOperator = 'in' | 'gt' | 'gte' | 'lt' | 'lte' | 'eq'
+
+export interface AnnouncementCondition {
+  type: AnnouncementConditionType
+  operator: AnnouncementOperator
+  group_ids?: number[]
+  value?: number
+}
+
+export interface AnnouncementConditionGroup {
+  all_of?: AnnouncementCondition[]
+}
+
+export interface AnnouncementTargeting {
+  any_of?: AnnouncementConditionGroup[]
+}
+
+export interface Announcement {
+  id: number
+  title: string
+  content: string
+  status: AnnouncementStatus
+  targeting: AnnouncementTargeting
+  starts_at?: string
+  ends_at?: string
+  created_by?: number
+  updated_by?: number
+  created_at: string
+  updated_at: string
+}
+
+export interface UserAnnouncement {
+  id: number
+  title: string
+  content: string
+  starts_at?: string
+  ends_at?: string
+  read_at?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface CreateAnnouncementRequest {
+  title: string
+  content: string
+  status?: AnnouncementStatus
+  targeting: AnnouncementTargeting
+  starts_at?: number
+  ends_at?: number
+}
+
+export interface UpdateAnnouncementRequest {
+  title?: string
+  content?: string
+  status?: AnnouncementStatus
+  targeting?: AnnouncementTargeting
+  starts_at?: number
+  ends_at?: number
+}
+
+export interface AnnouncementUserReadStatus {
+  user_id: number
+  email: string
+  username: string
+  balance: number
+  eligible: boolean
+  read_at?: string
+}
+
 // ==================== Proxy Node Types ====================
 
 export interface ProxyNode {