feat: add unified client timeline query

frontend/prisma/schema.prisma

@@ -58,6 +58,12 @@ enum WorkspaceDocumentType {
   Template
 }
 
+enum ClientTimelineContentType {
+  CALENDAR_EVENT
+  DOCUMENT
+  RECOMMENDATION
+}
+
 model Team {
   id        String   @id @default(cuid())
   name      String
@@ -79,6 +85,7 @@ model Team {
   feedCards   FeedCard[]
   contactPins ContactPin[]
   documents   WorkspaceDocument[]
+  clientTimelineEntries ClientTimelineEntry[]
   contactInboxes      ContactInbox[]
   contactInboxPreferences ContactInboxPreference[]
 }
@@ -137,6 +144,7 @@ model Contact {
   omniMessages   OmniMessage[]
   omniIdentities OmniContactIdentity[]
   contactInboxes ContactInbox[]
+  clientTimelineEntries ClientTimelineEntry[]
 
   @@index([teamId, updatedAt])
 }
@@ -436,3 +444,21 @@ model WorkspaceDocument {
 
   @@index([teamId, updatedAt])
 }
+
+model ClientTimelineEntry {
+  id          String                    @id @default(cuid())
+  teamId      String
+  contactId   String
+  contentType ClientTimelineContentType
+  contentId   String
+  datetime    DateTime                  @default(now())
+  createdAt   DateTime                  @default(now())
+  updatedAt   DateTime                  @updatedAt
+
+  team    Team    @relation(fields: [teamId], references: [id], onDelete: Cascade)
+  contact Contact @relation(fields: [contactId], references: [id], onDelete: Cascade)
+
+  @@unique([teamId, contentType, contentId])
+  @@index([teamId, contactId, datetime])
+  @@index([contactId, datetime])
+}