feat(conversations): add search endpoint — M1-006 (#299)

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

apps/gateway/src/conversations/conversations.dto.ts

@@ -1,12 +1,35 @@
 import {
   IsBoolean,
   IsIn,
+  IsInt,
   IsObject,
   IsOptional,
   IsString,
   IsUUID,
+  Max,
   MaxLength,
+  Min,
 } from 'class-validator';
+import { Type } from 'class-transformer';
+
+export class SearchMessagesDto {
+  @IsString()
+  @MaxLength(500)
+  q!: string;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(1)
+  @Max(100)
+  limit?: number = 20;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(0)
+  offset?: number = 0;
+}
 
 export class CreateConversationDto {
   @IsOptional()