feat(orchestrator): MS23 per-agent message history and SSE stream (#702)

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

apps/orchestrator/src/api/agents/dto/get-messages-query.dto.spec.ts

@@ -0,0 +1,37 @@
+import { plainToInstance } from "class-transformer";
+import { validate } from "class-validator";
+import { describe, expect, it } from "vitest";
+import { GetMessagesQueryDto } from "./get-messages-query.dto";
+
+describe("GetMessagesQueryDto", () => {
+  it("should use defaults when empty", async () => {
+    const dto = plainToInstance(GetMessagesQueryDto, {});
+    const errors = await validate(dto);
+
+    expect(errors).toHaveLength(0);
+    expect(dto.limit).toBe(50);
+    expect(dto.skip).toBe(0);
+  });
+
+  it("should reject limit greater than 200", async () => {
+    const dto = plainToInstance(GetMessagesQueryDto, {
+      limit: 201,
+      skip: 0,
+    });
+    const errors = await validate(dto);
+
+    expect(errors.length).toBeGreaterThan(0);
+    expect(errors.some((error) => error.property === "limit")).toBe(true);
+  });
+
+  it("should reject negative skip", async () => {
+    const dto = plainToInstance(GetMessagesQueryDto, {
+      limit: 50,
+      skip: -1,
+    });
+    const errors = await validate(dto);
+
+    expect(errors.length).toBeGreaterThan(0);
+    expect(errors.some((error) => error.property === "skip")).toBe(true);
+  });
+});

apps/orchestrator/src/api/agents/dto/get-messages-query.dto.ts

@@ -0,0 +1,17 @@
+import { Type } from "class-transformer";
+import { IsInt, IsOptional, Max, Min } from "class-validator";
+
+export class GetMessagesQueryDto {
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(1)
+  @Max(200)
+  limit = 50;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(0)
+  skip = 0;
+}