feat: remove legacy alert rules, superseded by automations

Alert rules already auto-migrate into automations on boot and the old
engine stands down after. Deletes the rule/firing tables, routes, UI,
and AI tools; keeps notification channels since automations still use
them. Also fixes automations' notify step, which still called the
deleted repository.

src/backend/tests/plugins/ai/context.test.ts

@@ -6,12 +6,12 @@ const BASE = { hostCount: 3, allowReadOnlyCommands: false };
 describe("buildSystemPrompt", () => {
   it("tells the assistant to stay inside what was asked", () => {
     // Without these the assistant answered "what is running on this server"
-    // by also proposing a monitoring script and an alert rule nobody wanted.
+    // by also proposing a monitoring script and an automation nobody wanted.
     const prompt = buildSystemPrompt(BASE);
 
     expect(prompt).toContain("nothing beyond it");
     expect(prompt).toMatch(/Read, then report\. Do not propose anything\./);
-    expect(prompt).toMatch(/no monitoring, no alert rules, no scripts/);
+    expect(prompt).toMatch(/no monitoring automations, no scripts/);
     expect(prompt).toMatch(/One request means one proposal at most/);
   });
 

src/backend/tests/plugins/ai/tools/proposal-executor.test.ts

@@ -13,14 +13,12 @@ const snippetRepository = {
   deleteSnippet: vi.fn(),
 };
 const fleetRepository = { create: vi.fn(), addMember: vi.fn() };
-const alertRepository = { createAlertRule: vi.fn() };
 const automationRepository = { create: vi.fn() };
 
 vi.mock("../../../../database/repositories/factory.js", () => ({
   createCurrentHostRepository: () => hostRepository,
   createCurrentSnippetRepository: () => snippetRepository,
   createCurrentFleetRepository: () => fleetRepository,
-  createCurrentAlertRepository: () => alertRepository,
   createCurrentAutomationRepository: () => automationRepository,
 }));
 

src/backend/tests/plugins/host-metrics/alert-engine-superseded.test.ts

@@ -1,86 +0,0 @@
-import { beforeEach, describe, expect, it, vi } from "vitest";
-
-/**
- * Once the alert rules have been migrated into automations, both systems hold
- * a copy of every rule. If the old engine kept evaluating, every alert would
- * be delivered twice.
- */
-
-const listEnabledRulesForHost = vi.fn();
-const listEnabledRulesForHostUser = vi.fn();
-const createFiring = vi.fn();
-
-vi.mock("../../../database/repositories/factory.js", () => ({
-  createCurrentAlertRepository: () => ({
-    listEnabledRulesForHost,
-    listEnabledRulesForHostUser,
-    createFiring,
-    pruneFiringsOlderThan: vi.fn(),
-    listEnabledChannelsForRule: vi.fn(async () => []),
-    findRuleById: vi.fn(async () => null),
-    getHostDisplayName: vi.fn(async () => "host"),
-  }),
-}));
-
-vi.mock("../../../utils/logger.js", () => ({
-  statsLogger: { warn: vi.fn(), info: vi.fn(), error: vi.fn() },
-}));
-
-vi.mock("../../../utils/notification-sender.js", () => ({
-  sendNotification: vi.fn(async () => undefined),
-}));
-
-vi.mock("../../../utils/discord-sender.js", () => ({
-  sendDiscord: vi.fn(async () => undefined),
-}));
-
-const alertEngineModule =
-  await import("../../../../../plugins/host-metrics/backend/alert-engine.js");
-
-const cpuRule = {
-  id: 1,
-  userId: "user-1",
-  hostId: null,
-  name: "CPU",
-  enabled: true,
-  triggerType: "cpu_threshold",
-  thresholdValue: 50,
-  thresholdDurationSeconds: 0,
-  cooldownMinutes: 0,
-};
-
-beforeEach(() => {
-  vi.clearAllMocks();
-  listEnabledRulesForHost.mockResolvedValue([cpuRule]);
-  listEnabledRulesForHostUser.mockResolvedValue([cpuRule]);
-});
-
-describe("AlertEngine before migration", () => {
-  it("still evaluates rules", async () => {
-    expect(alertEngineModule.isAlertEngineSuperseded()).toBe(false);
-
-    await alertEngineModule.AlertEngine.getInstance().evaluateMetrics(7, {
-      cpu: { percent: 90 },
-    });
-
-    expect(listEnabledRulesForHost).toHaveBeenCalled();
-  });
-});
-
-describe("AlertEngine after migration", () => {
-  it("stops evaluating every trigger type", async () => {
-    alertEngineModule.markAlertEngineSuperseded();
-    expect(alertEngineModule.isAlertEngineSuperseded()).toBe(true);
-
-    const engine = alertEngineModule.AlertEngine.getInstance();
-    await engine.evaluateMetrics(7, { cpu: { percent: 99 } });
-    await engine.evaluateStatus(7, false);
-    await engine.evaluateHealthCheck(7, "user-1", "web", false);
-    await engine.evaluateUserLogin(7, "user-1", "root", "10.0.0.1");
-
-    // Nothing is even loaded, so nothing can be delivered a second time.
-    expect(listEnabledRulesForHost).not.toHaveBeenCalled();
-    expect(listEnabledRulesForHostUser).not.toHaveBeenCalled();
-    expect(createFiring).not.toHaveBeenCalled();
-  });
-});

src/backend/tests/plugins/host-metrics/login-alert-dispatch.test.ts

@@ -26,7 +26,6 @@ const route = ast.statements.find(
 );
 if (!route) throw new Error("Login event route is missing");
 const notify = vi.fn();
-const legacy = vi.fn().mockResolvedValue(undefined);
 let handler: (req: unknown, res: unknown) => Promise<void>;
 runInNewContext(
   ts.transpileModule(route.getText(ast), {
@@ -49,7 +48,6 @@ runInNewContext(
       },
     }),
     notifyAutomationInternalEvent: notify,
-    AlertEngine: { getInstance: () => ({ evaluateUserLogin: legacy }) },
   },
 );
 const body = {
@@ -61,7 +59,7 @@ const body = {
 const response = () => ({ status: vi.fn().mockReturnThis(), json: vi.fn() });
 beforeEach(() => vi.clearAllMocks());
 
-it("delivers successful SSH login details to automations while retaining the legacy hook", async () => {
+it("delivers successful SSH login details to automations", async () => {
   const res = response();
   await handler(
     {
@@ -75,12 +73,6 @@ it("delivers successful SSH login details to automations while retaining the leg
     sshUser: "alice",
     fromIp: "192.0.2.4",
   });
-  expect(legacy).toHaveBeenCalledExactlyOnceWith(
-    42,
-    "owner",
-    "alice",
-    "192.0.2.4",
-  );
   expect(res.json).toHaveBeenCalledWith({ ok: true });
 });
 
@@ -101,6 +93,5 @@ it.each([
     );
     expect(res.status).toHaveBeenCalledWith(403);
     expect(notify).not.toHaveBeenCalled();
-    expect(legacy).not.toHaveBeenCalled();
   },
 );