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/grafana/provisioning/datasources/datasource.yml

@@ -1,12 +0,0 @@
-# Auto-provisions the Prometheus datasource the CCAM dashboard queries. The uid
-# is fixed so the bundled dashboard JSON can reference it deterministically.
-apiVersion: 1
-
-datasources:
-  - name: Prometheus
-    type: prometheus
-    uid: ccam-prometheus
-    access: proxy
-    url: http://prometheus:9090
-    isDefault: true
-    editable: true