feat: auth middleware, brain data layer, Valkey queue (P1-002/003/004) (#71)

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

packages/brain/src/conversations.ts

@@ -0,0 +1,49 @@
+import { eq, type Db, conversations, messages } from '@mosaic/db';
+
+export type Conversation = typeof conversations.$inferSelect;
+export type NewConversation = typeof conversations.$inferInsert;
+export type Message = typeof messages.$inferSelect;
+export type NewMessage = typeof messages.$inferInsert;
+
+export function createConversationsRepo(db: Db) {
+  return {
+    async findAll(userId: string): Promise<Conversation[]> {
+      return db.select().from(conversations).where(eq(conversations.userId, userId));
+    },
+
+    async findById(id: string): Promise<Conversation | undefined> {
+      const rows = await db.select().from(conversations).where(eq(conversations.id, id));
+      return rows[0];
+    },
+
+    async create(data: NewConversation): Promise<Conversation> {
+      const rows = await db.insert(conversations).values(data).returning();
+      return rows[0]!;
+    },
+
+    async update(id: string, data: Partial<NewConversation>): Promise<Conversation | undefined> {
+      const rows = await db
+        .update(conversations)
+        .set({ ...data, updatedAt: new Date() })
+        .where(eq(conversations.id, id))
+        .returning();
+      return rows[0];
+    },
+
+    async remove(id: string): Promise<boolean> {
+      const rows = await db.delete(conversations).where(eq(conversations.id, id)).returning();
+      return rows.length > 0;
+    },
+
+    async findMessages(conversationId: string): Promise<Message[]> {
+      return db.select().from(messages).where(eq(messages.conversationId, conversationId));
+    },
+
+    async addMessage(data: NewMessage): Promise<Message> {
+      const rows = await db.insert(messages).values(data).returning();
+      return rows[0]!;
+    },
+  };
+}
+
+export type ConversationsRepo = ReturnType<typeof createConversationsRepo>;