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/agent-memory.service.ts

@@ -0,0 +1,79 @@
+import { Injectable, NotFoundException } from "@nestjs/common";
+import { PrismaService } from "../prisma/prisma.service";
+import { Prisma } from "@prisma/client";
+import type { UpsertAgentMemoryDto } from "./dto";
+
+@Injectable()
+export class AgentMemoryService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  /**
+   * Upsert a memory entry for an agent.
+   */
+  async upsert(workspaceId: string, agentId: string, key: string, dto: UpsertAgentMemoryDto) {
+    return this.prisma.agentMemory.upsert({
+      where: {
+        workspaceId_agentId_key: { workspaceId, agentId, key },
+      },
+      create: {
+        workspaceId,
+        agentId,
+        key,
+        value: dto.value as Prisma.InputJsonValue,
+      },
+      update: {
+        value: dto.value as Prisma.InputJsonValue,
+      },
+    });
+  }
+
+  /**
+   * List all memory entries for an agent in a workspace.
+   */
+  async findAll(workspaceId: string, agentId: string) {
+    return this.prisma.agentMemory.findMany({
+      where: { workspaceId, agentId },
+      orderBy: { key: "asc" },
+    });
+  }
+
+  /**
+   * Get a single memory entry by key.
+   */
+  async findOne(workspaceId: string, agentId: string, key: string) {
+    const entry = await this.prisma.agentMemory.findUnique({
+      where: {
+        workspaceId_agentId_key: { workspaceId, agentId, key },
+      },
+    });
+
+    if (!entry) {
+      throw new NotFoundException(`Memory key "${key}" not found for agent "${agentId}"`);
+    }
+
+    return entry;
+  }
+
+  /**
+   * Delete a memory entry by key.
+   */
+  async remove(workspaceId: string, agentId: string, key: string) {
+    const entry = await this.prisma.agentMemory.findUnique({
+      where: {
+        workspaceId_agentId_key: { workspaceId, agentId, key },
+      },
+    });
+
+    if (!entry) {
+      throw new NotFoundException(`Memory key "${key}" not found for agent "${agentId}"`);
+    }
+
+    await this.prisma.agentMemory.delete({
+      where: {
+        workspaceId_agentId_key: { workspaceId, agentId, key },
+      },
+    });
+
+    return { message: "Memory entry deleted successfully" };
+  }
+}