feat: make each plugin an npm workspace built by a termix-plugin CLI

plugins/host-metrics/src/backend/automation-bridge.ts

@@ -0,0 +1,81 @@
+/**
+ * One-line hand-off from the metrics poller onto the ctx.events bus.
+ *
+ * The poller is already a very large module, so the hooks it calls live here
+ * instead. Everything is fire-and-forget: a failure in a subscriber must never
+ * disturb metric collection, and publishing onto the bus creates no static edge
+ * to the automations layer (which reads repositories the metrics module also
+ * pulls in).
+ *
+ * For the generic (non-metrics) internal event notifier, see
+ * `hosts/automation-events.ts` -- that one is shared across features.
+ */
+
+import {
+  pluginEvents,
+  TOPICS,
+} from "../../../../src/backend/plugins/events.js";
+import type { MetricsSnapshot } from "../../../automations/src/backend/conditions.js";
+
+export interface HostMetricsPayload {
+  hostId: number;
+  ownerUserId: string;
+  metrics: MetricsSnapshot;
+}
+
+export interface HostStatusPayload {
+  hostId: number;
+  ownerUserId: string;
+  online: boolean;
+}
+
+export interface HostHealthCheckPayload {
+  hostId: number;
+  userId: string;
+  checkId: string;
+  ok: boolean;
+  detail?: string;
+}
+
+export function notifyAutomationMetrics(
+  hostId: number,
+  ownerUserId: string,
+  metrics: MetricsSnapshot,
+): void {
+  if (!ownerUserId) return;
+  pluginEvents.emit(TOPICS.hostMetrics, {
+    hostId,
+    ownerUserId,
+    metrics,
+  } satisfies HostMetricsPayload);
+}
+
+export function notifyAutomationStatus(
+  hostId: number,
+  ownerUserId: string,
+  online: boolean,
+): void {
+  if (!ownerUserId) return;
+  pluginEvents.emit(TOPICS.hostStatus, {
+    hostId,
+    ownerUserId,
+    online,
+  } satisfies HostStatusPayload);
+}
+
+export function notifyAutomationHealthCheck(
+  hostId: number,
+  userId: string,
+  checkId: string,
+  ok: boolean,
+  detail?: string,
+): void {
+  if (!userId) return;
+  pluginEvents.emit(TOPICS.hostHealthCheck, {
+    hostId,
+    userId,
+    checkId,
+    ok,
+    detail,
+  } satisfies HostHealthCheckPayload);
+}