chore: remove unused desktop app, cloud deployment infra, and monitoring stack

Deletes desktop/ (Electron wrapper), deployments/ (Helm/Kustomize/
Terraform/CI for cloud deploy), and monitoring/ (Prometheus + Grafana
stack) along with DESKTOP.md, DEPLOYMENT.md, docker-compose.full.yml,
their npm scripts, and every dangling reference across README,
ARCHITECTURE, INSTALL, SETUP, docs/, and the repeated per-file
MODULE_GUIDE "Observability" boilerplate comment. The GET /api/metrics
endpoint itself is untouched — it's the dashboard's own route, not
part of the removed monitoring stack.

server/__tests__/monitoring-paths.test.js

@@ -1,53 +0,0 @@
-/**
- * @file Unit tests for cross-platform monitoring binary URL/path resolution.
- * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
- */
-const { describe, it } = require("node:test");
-const assert = require("node:assert/strict");
-const {
-  prometheusUrl,
-  grafanaUrl,
-  prometheusArchiveExt,
-  grafanaArchiveExt,
-  prometheusPlatform,
-  prometheusArchiveName,
-  grafanaArchiveName,
-  toGrafanaPath,
-} = require("../../monitoring/scripts/paths");
-
-describe("monitoring paths", () => {
-  it("builds official download URLs for the current platform", () => {
-    const plat = prometheusPlatform();
-    const promExt = prometheusArchiveExt();
-    const grafExt = grafanaArchiveExt();
-
-    assert.match(
-      prometheusUrl(),
-      new RegExp(`${prometheusArchiveName()}\\.${promExt.replace(".", "\\.")}$`)
-    );
-    assert.match(
-      grafanaUrl(),
-      new RegExp(`grafana-[0-9.]+\\.${plat}\\.${grafExt.replace(".", "\\.")}$`)
-    );
-
-    if (process.platform === "win32") {
-      assert.equal(promExt, "zip");
-      assert.equal(grafExt, "zip");
-    } else {
-      assert.equal(promExt, "tar.gz");
-      assert.equal(grafExt, "tar.gz");
-    }
-  });
-
-  it("normalizes Windows paths for Grafana YAML", () => {
-    assert.equal(
-      toGrafanaPath("C:\\ccam\\monitoring\\grafana\\dashboards"),
-      "C:/ccam/monitoring/grafana/dashboards"
-    );
-  });
-
-  it("uses consistent archive naming", () => {
-    assert.match(prometheusArchiveName(), /^prometheus-[0-9.]+\./);
-    assert.match(grafanaArchiveName(), /^grafana-[0-9.]+\./);
-  });
-});