fix: suppress false 'Unknown toolsets' warning for MCP server names (#5279)

MCP server names (e.g. annas, libgen) are added to enabled_toolsets by
_get_platform_tools() but aren't registered in TOOLSETS until later when
_sync_mcp_toolsets() runs during tool discovery. The validation in
HermesCLI.__init__() fires before that, producing a false warning.

Fix: exclude configured MCP server names from the validation check.
CLI_CONFIG is already available at the call site, so no new imports needed.

Closes #5267 (alternative fix)

cli.py

@@ -1257,8 +1257,11 @@ class HermesCLI:
         # Parse and validate toolsets
         self.enabled_toolsets = toolsets
         if toolsets and "all" not in toolsets and "*" not in toolsets:
-            # Validate each toolset
-            invalid = [t for t in toolsets if not validate_toolset(t)]
+            # Validate each toolset — MCP server names are added by
+            # _get_platform_tools() but aren't registered in TOOLSETS yet
+            # (that happens later in _sync_mcp_toolsets), so exclude them.
+            mcp_names = set((CLI_CONFIG.get("mcp_servers") or {}).keys())
+            invalid = [t for t in toolsets if not validate_toolset(t) and t not in mcp_names]
             if invalid:
                 self.console.print(f"[bold red]Warning: Unknown toolsets: {', '.join(invalid)}[/]")