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.

monitoring/prometheus/prometheus.yml

@@ -1,29 +0,0 @@
-# Prometheus scrape config for the CCAM dashboard's /api/metrics endpoint.
-#
-# CCAM normally runs on the HOST (a plain `npm start` on port 4820), so from
-# inside the Prometheus container it is reached via host.docker.internal. If the
-# dashboard runs elsewhere or on a different port, edit the `targets` below.
-#
-# IMPORTANT: the CCAM server's DNS-rebinding guard rejects any Host header that
-# is not loopback, so a container scrape gets 403 EBADHOST until you start the
-# server allowing this Host:
-#     DASHBOARD_ALLOWED_HOSTS=host.docker.internal npm start
-# (and, if DASHBOARD_TOKEN is set, also uncomment the authorization block below).
-# See ../README.md.
-global:
-  scrape_interval: 15s
-  scrape_timeout: 10s
-
-rule_files:
-  - ccam-rules.yml
-
-scrape_configs:
-  - job_name: ccam
-    metrics_path: /api/metrics
-    static_configs:
-      - targets: ["host.docker.internal:4820"]
-    # If the server sets DASHBOARD_TOKEN (LAN deployments), uncomment and fill in
-    # so the scrape passes the same-origin/token guard:
-    # authorization:
-    #   type: Bearer
-    #   credentials: "<DASHBOARD_TOKEN>"