feat: Add Option 3 - Deploy Additional Server with multi-server support

Major features:
- Automated SSH key setup between remote and core servers
- Docker TLS configuration with shared CA certificates
- Automatic deployment of Dockge, Traefik, Sablier, and Infrastructure stacks
- Copy all stacks (except core) to remote server for on-demand deployment
- New standalone Traefik stack for remote server container discovery
- Locale-aware SSH/SCP commands to handle Raspberry Pi warnings
- Variable expansion support in .env files (${VAR} references)
- Comprehensive error handling and verbose deployment logging

Technical improvements:
- setup_ssh_key_to_core() - Automated RSA 4096-bit key generation and installation
- setup_multi_server_tls() - Fetch shared CA from core server via SSH
- copy_all_stacks_for_remote() - Deploy all stacks except core
- deploy_traefik_stack() - Local Traefik for container discovery
- Enhanced localization with envsubst support
- Docker network creation (traefik-network, homelab-network)
- Password authentication with special character handling

Fixes:
- Fixed SSH key path handling for non-root users
- Fixed SCP exit code checking (was checking grep instead of scp)
- Fixed CA file detection with proper test commands
- Removed unnecessary prepare_deployment() function call
- Added ACTUAL_USER variable initialization for remote deployments

docker-compose/traefik/docker-compose.yml

@@ -0,0 +1,40 @@
+# Traefik Service for Remote Servers
+# This standalone Traefik instance runs on remote servers to discover local containers
+# and communicate with the core Traefik on the core server via Docker TLS
+
+services:
+  traefik:
+    # Local Traefik instance for container discovery on this remote server
+    image: traefik:v3
+    container_name: traefik
+    restart: unless-stopped
+    command:
+      - '--api.dashboard=true'
+      - '--api.insecure=false'
+      - '--providers.docker=true'
+      - '--providers.docker.exposedbydefault=false'
+      - '--providers.docker.network=traefik-network'
+      - '--providers.file.directory=/dynamic'
+      - '--providers.file.watch=true'
+      - '--log.level=INFO'
+      - '--accesslog=true'
+      - '--entrypoints.web.address=:80'
+      - '--entrypoints.websecure.address=:443'
+    environment:
+      - TZ=America/New_York
+    ports:
+      - '8080:8080'  # Dashboard (optional, for debugging)
+    volumes:
+      - ./config:/config
+      - ./dynamic:/dynamic
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    networks:
+      - traefik-network
+    labels:
+      - 'homelab.category=infrastructure'
+      - 'homelab.description=Local reverse proxy for container discovery'
+      - 'traefik.enable=false'  # This Traefik doesn't route itself
+
+networks:
+  traefik-network:
+    external: true