feat(api): profil machine éditable, sonde, et réglages globaux apt-cacher-ng

- machines : updateMachine (PATCH /machines/:id) + POST /machines/:id/probe
  (sonde synchrone → faits + proposition de correction) ; MachineView expose
  machineKind/virtualization ; CreateMachineInput accepte aptProxyMode persistent
- app_settings (clé/valeur, migration 0006) + service appSettings :
  défaut apt-cacher-ng (mode + url) ; applyProxyToAllMachines
- routes /settings : GET, PUT /apt-proxy, POST /apt-proxy/apply-all

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

server/routes/index.ts

@@ -5,6 +5,7 @@ import { actionsRoutes } from "./actions.js";
 import { actionRequestsRoutes } from "./actionRequests.js";
 import { dockerRoutes } from "./docker.js";
 import { dbRoutes } from "./db.js";
+import { settingsRoutes } from "./settings.js";
 import { getServerCapabilities } from "../services/capabilities.js";
 import { getSystemMetrics, getSystemStatus } from "../services/system.js";
 
@@ -13,6 +14,7 @@ api.get("/capabilities", (c) => c.json(getServerCapabilities()));
 api.get("/system/status", (c) => c.json(getSystemStatus()));
 api.get("/system/metrics", (c) => c.json(getSystemMetrics()));
 api.route("/system/db", dbRoutes);
+api.route("/settings", settingsRoutes);
 api.route("/machines", machinesRoutes);
 api.route("/machines", actionsRoutes);
 api.route("/machines", dockerRoutes);