feat(events): timeline d'événements machine (tâche 5 backlog)

- listMachineEvents (machine_events, 30 derniers, desc) + route GET /machines/:id/events
- api machineEvents ; section repliable « Timeline » dans le panneau détail
  (badge sévérité + horodatage), exploite les events déjà enregistrés par recordEvent

tsc 0 · 118 tests · build OK.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/routes/machines.ts

@@ -10,6 +10,7 @@ import { runProbe } from "../services/machineProbe.js";
 import { collectMetrics, getLatestMetrics } from "../services/machineMetrics.js";
 import { analyzeMachineRepositories } from "../services/aptRepositories.js";
 import { listImportantMessages, acknowledgeMessage } from "../services/importantMessages.js";
+import { listMachineEvents } from "../services/machineState.js";
 
 export const machinesRoutes = new Hono();
 
@@ -78,6 +79,9 @@ machinesRoutes.post("/:id/apt-repositories", async (c) => {
   }
 });
 
+// Timeline d'événements machine.
+machinesRoutes.get("/:id/events", (c) => c.json(listMachineEvents(c.req.param("id"))));
+
 // Messages importants (warnings/erreurs/évolutions) extraits des sorties.
 machinesRoutes.get("/:id/messages", (c) => c.json(listImportantMessages(c.req.param("id"))));
 machinesRoutes.post("/:id/messages/:msgId/ack", (c) => {