feat: achieve CLI parity with Central UI

Add 33 new management message records, ManagementActor handlers, and CLI
commands to close all functionality gaps between the Central UI and the
Management CLI. New capabilities include:

- Template member CRUD (attributes, alarms, scripts, compositions)
- Shared script CRUD
- Database connection definition CRUD
- Inbound API method CRUD
- LDAP scope rule management
- API key enable/disable
- Area update
- Remote event log and parked message queries
- Missing get/update commands for templates, sites, instances, data
  connections, external systems, notifications, and SMTP config

Includes 12 new ManagementActor unit tests covering authorization,
happy-path queries, and error handling. Updates CLI README and component
design documents (Component-CLI.md, Component-ManagementService.md).

src/ScadaLink.CLI/Commands/DataConnectionCommands.cs

@@ -11,13 +11,69 @@ public static class DataConnectionCommands
         var command = new Command("data-connection") { Description = "Manage data connections" };
 
         command.Add(BuildList(contactPointsOption, formatOption));
+        command.Add(BuildGet(contactPointsOption, formatOption));
         command.Add(BuildCreate(contactPointsOption, formatOption));
+        command.Add(BuildUpdate(contactPointsOption, formatOption));
         command.Add(BuildDelete(contactPointsOption, formatOption));
         command.Add(BuildAssign(contactPointsOption, formatOption));
+        command.Add(BuildUnassign(contactPointsOption, formatOption));
 
         return command;
     }
 
+    private static Command BuildGet(Option<string> contactPointsOption, Option<string> formatOption)
+    {
+        var idOption = new Option<int>("--id") { Description = "Data connection ID", Required = true };
+        var cmd = new Command("get") { Description = "Get a data connection by ID" };
+        cmd.Add(idOption);
+        cmd.SetAction(async (ParseResult result) =>
+        {
+            var id = result.GetValue(idOption);
+            return await CommandHelpers.ExecuteCommandAsync(
+                result, contactPointsOption, formatOption, new GetDataConnectionCommand(id));
+        });
+        return cmd;
+    }
+
+    private static Command BuildUpdate(Option<string> contactPointsOption, Option<string> formatOption)
+    {
+        var idOption = new Option<int>("--id") { Description = "Data connection ID", Required = true };
+        var nameOption = new Option<string>("--name") { Description = "Connection name", Required = true };
+        var protocolOption = new Option<string>("--protocol") { Description = "Protocol", Required = true };
+        var configOption = new Option<string?>("--configuration") { Description = "Configuration JSON" };
+
+        var cmd = new Command("update") { Description = "Update a data connection" };
+        cmd.Add(idOption);
+        cmd.Add(nameOption);
+        cmd.Add(protocolOption);
+        cmd.Add(configOption);
+        cmd.SetAction(async (ParseResult result) =>
+        {
+            var id = result.GetValue(idOption);
+            var name = result.GetValue(nameOption)!;
+            var protocol = result.GetValue(protocolOption)!;
+            var config = result.GetValue(configOption);
+            return await CommandHelpers.ExecuteCommandAsync(
+                result, contactPointsOption, formatOption,
+                new UpdateDataConnectionCommand(id, name, protocol, config));
+        });
+        return cmd;
+    }
+
+    private static Command BuildUnassign(Option<string> contactPointsOption, Option<string> formatOption)
+    {
+        var idOption = new Option<int>("--assignment-id") { Description = "Assignment ID", Required = true };
+        var cmd = new Command("unassign") { Description = "Unassign a data connection from a site" };
+        cmd.Add(idOption);
+        cmd.SetAction(async (ParseResult result) =>
+        {
+            var id = result.GetValue(idOption);
+            return await CommandHelpers.ExecuteCommandAsync(
+                result, contactPointsOption, formatOption, new UnassignDataConnectionFromSiteCommand(id));
+        });
+        return cmd;
+    }
+
     private static Command BuildList(Option<string> contactPointsOption, Option<string> formatOption)
     {
         var cmd = new Command("list") { Description = "List all data connections" };