feat(demo): add complete TSYS developer support stack demo implementation

Add full demo environment with 13 services across 4 categories:
- Infrastructure: Homepage, Docker Socket Proxy, Pi-hole, Portainer
- Monitoring: InfluxDB, Grafana
- Documentation: Draw.io, Kroki
- Developer Tools: Atomic Tracker, ArchiveBox, Tube Archivist,
  Wakapi, MailHog, Atuin

Includes:
- Docker Compose templates with dynamic environment configuration
- Deployment orchestration scripts with user ID detection
- Comprehensive test suite (unit, integration, e2e)
- Pre-deployment validation with yamllint, shellcheck
- Full documentation (PRD, AGENTS, README)
- Service configurations for all components

All services configured for demo purposes with:
- Dynamic UID/GID mapping
- Docker socket proxy security
- Health checks and monitoring
- Service discovery via Homepage labels

Ports allocated 4000-4099 range with sequential assignment.

💘 Generated with Crush

Assisted-by: GLM-4.7 via Crush <crush@charm.land>

demo/.proselintrc

@@ -0,0 +1,6 @@
+{
+  "flags": [
+    "typography.symbols.curly_quotes",
+    "leonard.exclamation.30ppm"
+  ]
+}