feat(api): add agent memory module (MS22-DB-002, MS22-API-002) (#586)

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

apps/api/src/agent-memory/dto/index.ts

@@ -0,0 +1 @@
+export * from "./upsert-agent-memory.dto";

apps/api/src/agent-memory/dto/upsert-agent-memory.dto.ts

@@ -0,0 +1,10 @@
+import { IsNotEmpty } from "class-validator";
+
+/**
+ * DTO for upserting an agent memory entry.
+ * The value accepts any JSON-serializable data.
+ */
+export class UpsertAgentMemoryDto {
+  @IsNotEmpty({ message: "value must not be empty" })
+  value!: unknown;
+}