feat: implement modular lab tool structure with working CLI

- Add lab/ module structure (core, machines, deployment, monitoring)
- Add mcp/ server stub for future MCP integration
- Update main.scm to use new modular architecture
- Fix utils/config.scm to export get-current-config function
- Create comprehensive test suite with all modules passing
- Update TODO.md with completed high priority tasks

Key improvements:
- Modular design following K.I.S.S principles
- Working CLI interface for status, machines, deploy commands
- Infrastructure status checking functional
- All module tests passing
- Clean separation of pure/impure functions

CLI now works: ./main.scm status, ./main.scm machines, ./main.scm deploy <machine>

packages/lab-tool/utils/config.scm

@@ -13,7 +13,8 @@
             get-all-machines
             validate-machine-name
             get-homelab-root
-            get-ssh-config))
+            get-ssh-config
+            get-current-config))
 
 ;; Default configuration
 (define default-config
@@ -125,5 +126,10 @@
             (is-local . ,(eq? type 'local))))
         #f)))
 
+;; Get current configuration
+(define (get-current-config)
+  "Get current loaded configuration"
+  current-config)
+
 ;; Initialize configuration on module load
 (load-config)