feat: add GET /api/feed endpoint

Expose the user's current feed via GET /api/feed. Returns
cached feed from engine.lastFeed(), falling back to
engine.refresh() when no cache exists.

Auth middleware is injected as a dependency to allow test
substitution via mockAuthSessionMiddleware.

Co-authored-by: Ona <no-reply@ona.com>

apps/aris-backend/src/feed/http.test.ts

@@ -0,0 +1,140 @@
+import type { ActionDefinition, Context, FeedItem, FeedSource } from "@aris/core"
+
+import { describe, expect, test } from "bun:test"
+import { Hono } from "hono"
+
+import { mockAuthSessionMiddleware } from "../auth/session-middleware.ts"
+import { UserSessionManager } from "../session/index.ts"
+import { registerFeedHttpHandlers } from "./http.ts"
+
+interface FeedResponse {
+	items: Array<{
+		id: string
+		type: string
+		priority: number
+		timestamp: string
+		data: Record<string, unknown>
+	}>
+	errors: Array<{ sourceId: string; error: string }>
+}
+
+function createStubSource(id: string, items: FeedItem[] = []): FeedSource {
+	return {
+		id,
+		async listActions(): Promise<Record<string, ActionDefinition>> {
+			return {}
+		},
+		async executeAction(): Promise<unknown> {
+			return undefined
+		},
+		async fetchContext(): Promise<Partial<Context> | null> {
+			return null
+		},
+		async fetchItems() {
+			return items
+		},
+	}
+}
+
+function buildTestApp(sessionManager: UserSessionManager, userId?: string) {
+	const app = new Hono()
+	registerFeedHttpHandlers(app, {
+		sessionManager,
+		authSessionMiddleware: mockAuthSessionMiddleware(userId),
+	})
+	return app
+}
+
+describe("GET /api/feed", () => {
+	test("returns 401 without auth", async () => {
+		const manager = new UserSessionManager([])
+		const app = buildTestApp(manager)
+
+		const res = await app.request("/api/feed")
+
+		expect(res.status).toBe(401)
+	})
+
+	test("returns cached feed when available", async () => {
+		const items: FeedItem[] = [
+			{
+				id: "item-1",
+				type: "test",
+				priority: 0.8,
+				timestamp: new Date("2025-01-01T00:00:00.000Z"),
+				data: { value: 42 },
+			},
+		]
+		const manager = new UserSessionManager([() => createStubSource("test", items)])
+		const app = buildTestApp(manager, "user-1")
+
+		// Prime the cache
+		const session = manager.getOrCreate("user-1")
+		await session.engine.refresh()
+		expect(session.engine.lastFeed()).not.toBeNull()
+
+		const res = await app.request("/api/feed")
+
+		expect(res.status).toBe(200)
+		const body = (await res.json()) as FeedResponse
+		expect(body.items).toHaveLength(1)
+		expect(body.items[0]!.id).toBe("item-1")
+		expect(body.items[0]!.type).toBe("test")
+		expect(body.items[0]!.priority).toBe(0.8)
+		expect(body.items[0]!.timestamp).toBe("2025-01-01T00:00:00.000Z")
+		expect(body.errors).toHaveLength(0)
+	})
+
+	test("forces refresh when no cached feed", async () => {
+		const items: FeedItem[] = [
+			{
+				id: "fresh-1",
+				type: "test",
+				priority: 0.5,
+				timestamp: new Date("2025-06-01T12:00:00.000Z"),
+				data: { fresh: true },
+			},
+		]
+		const manager = new UserSessionManager([() => createStubSource("test", items)])
+		const app = buildTestApp(manager, "user-1")
+
+		// No prior refresh — lastFeed() returns null, handler should call refresh()
+		const res = await app.request("/api/feed")
+
+		expect(res.status).toBe(200)
+		const body = (await res.json()) as FeedResponse
+		expect(body.items).toHaveLength(1)
+		expect(body.items[0]!.id).toBe("fresh-1")
+		expect(body.items[0]!.data.fresh).toBe(true)
+		expect(body.errors).toHaveLength(0)
+	})
+
+	test("serializes source errors as message strings", async () => {
+		const failingSource: FeedSource = {
+			id: "failing",
+			async listActions() {
+				return {}
+			},
+			async executeAction() {
+				return undefined
+			},
+			async fetchContext() {
+				return null
+			},
+			async fetchItems() {
+				throw new Error("connection timeout")
+			},
+		}
+		const manager = new UserSessionManager([() => failingSource])
+		const app = buildTestApp(manager, "user-1")
+
+		const res = await app.request("/api/feed")
+
+		expect(res.status).toBe(200)
+		const body = (await res.json()) as FeedResponse
+		expect(body.items).toHaveLength(0)
+		expect(body.errors).toHaveLength(1)
+		expect(body.errors[0]!.sourceId).toBe("failing")
+		expect(body.errors[0]!.error).toBe("connection timeout")
+	})
+})