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/config/grafana/dashboards.yml

@@ -0,0 +1,14 @@
+---
+# TSYS Developer Support Stack - Grafana Dashboards Configuration
+apiVersion: 1
+
+providers:
+  - name: 'default'
+    orgId: 1
+    folder: ''
+    type: file
+    disableDeletion: false
+    updateIntervalSeconds: 10
+    allowUiUpdates: true
+    options:
+      path: /etc/grafana/provisioning/dashboards

demo/config/grafana/datasources.yml

@@ -0,0 +1,20 @@
+---
+# TSYS Developer Support Stack - Grafana Datasources Configuration
+apiVersion: 1
+
+datasources:
+  - name: InfluxDB
+    type: influxdb
+    access: proxy
+    url: http://influxdb:8086
+    database: demo_metrics
+    user: demo_admin
+    password: demo_password
+    isDefault: true
+    jsonData:
+      version: Flux
+      organization: tsysdemo
+      defaultBucket: demo_metrics
+      tlsSkipVerify: true
+    secureJsonData:
+      token: demo_token_replace_in_production

demo/config/homepage/docker.yaml

@@ -0,0 +1,34 @@
+---
+# TSYS Developer Support Stack - Homepage Configuration
+# This file will be automatically generated by Homepage service discovery
+
+providers:
+  openweathermap: openweathermapapikey
+  longshore: longshoreapikey
+
+widgets:
+  - resources:
+      cpu: true
+      memory: true
+      disk: true
+  - search:
+      provider: duckduckgo
+      target: _blank
+  - datetime:
+      format:
+        dateStyle: long
+        timeStyle: short
+        hour12: true
+
+bookmarks:
+  - Development:
+      - Github:
+          - abbr: GH
+            href: https://github.com/
+      - Docker Hub:
+          - abbr: DH
+            href: https://hub.docker.com/
+  - Documentation:
+      - TSYS Docs:
+          - abbr: TSYS
+            href: https://docs.tsys.dev/