feat(api): add conversation archive with vector search (MS22-DB-004, MS22-API-004) (#587)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/api/src/conversation-archive/dto/ingest-conversation.dto.ts

@@ -0,0 +1,64 @@
+import {
+  IsString,
+  IsArray,
+  IsOptional,
+  IsDateString,
+  MinLength,
+  MaxLength,
+  IsObject,
+  ValidateNested,
+  ArrayMinSize,
+} from "class-validator";
+import { Type } from "class-transformer";
+
+/**
+ * Represents a single message in a conversation session
+ */
+export class ConversationMessageDto {
+  @IsString()
+  role!: string;
+
+  @IsString()
+  @MinLength(1)
+  content!: string;
+
+  @IsOptional()
+  @IsDateString()
+  timestamp?: string;
+}
+
+/**
+ * DTO for ingesting a conversation session log
+ */
+export class IngestConversationDto {
+  @IsString()
+  @MinLength(1)
+  @MaxLength(500)
+  sessionId!: string;
+
+  @IsString()
+  @MinLength(1)
+  @MaxLength(500)
+  agentId!: string;
+
+  @IsArray()
+  @ArrayMinSize(1)
+  @ValidateNested({ each: true })
+  @Type(() => ConversationMessageDto)
+  messages!: ConversationMessageDto[];
+
+  @IsString()
+  @MinLength(1)
+  summary!: string;
+
+  @IsDateString()
+  startedAt!: string;
+
+  @IsOptional()
+  @IsDateString()
+  endedAt?: string;
+
+  @IsOptional()
+  @IsObject()
+  metadata?: Record<string, unknown>;
+}