Add Management Service and CLI components (design docs)

New components 18-19: ManagementService (Akka.NET actor on Central exposing
all admin operations via ClusterClientReceptionist) and CLI (console app using
ClusterClient for scripting). Updated HighLevelReqs, CLAUDE.md, README,
Component-Host, Component-Communication, Component-Security.

CLAUDE.md

@@ -36,7 +36,7 @@ There is no source code in this project — only design documentation in markdow
 - Use `git diff` to review changes before committing.
 - Commit related changes together with a descriptive message summarizing the design decision.
 
-## Current Component List (17 components)
+## Current Component List (19 components)
 
 1. Template Engine — Template modeling, inheritance, composition, validation, flattening, diffs.
 2. Deployment Manager — Central-side deployment pipeline, system-wide artifact deployment, instance lifecycle.
@@ -55,6 +55,8 @@ There is no source code in this project — only design documentation in markdow
 15. Host — Single deployable binary, role-based component registration, Akka.NET bootstrap.
 16. Commons — Shared types, POCO entity classes, repository interfaces, message contracts.
 17. Configuration Database — EF Core data access layer, repositories, unit-of-work, audit logging (IAuditService), migrations.
+18. Management Service — Akka.NET actor providing programmatic access to all admin operations, ClusterClientReceptionist registration.
+19. CLI — Command-line tool using ClusterClient to interact with Management Service, System.CommandLine, JSON/table output.
 
 ## Key Design Decisions (for context across sessions)