feat(irc): add interactive setup

feat(gateway): refine Platform._missing_ and platform-connected dispatch

Restricts plugin-name acceptance to bundled plugin scan + registry
(no arbitrary string -> enum-pollution), pulls per-platform connectivity
checks into a _PLATFORM_CONNECTED_CHECKERS lambda map with a clean
_is_platform_connected method, and adds tests covering the checker map,
plugin platform interface, and IRC setup wizard.

ui-tui/src/types.ts

@@ -142,12 +142,12 @@ export interface McpServerStatus {
 
 export interface SessionInfo {
   cwd?: string
-  fast?: boolean
-  lazy?: boolean
-  mcp_servers?: McpServerStatus[]
-  model: string
-  reasoning_effort?: string
-  release_date?: string
+  fast?: boolean;
+  lazy?: boolean;
+  mcp_servers?: McpServerStatus[];
+  model: string;
+  reasoning_effort?: string;
+  release_date?: string;
   service_tier?: string
   skills: Record<string, string[]>
   tools: Record<string, string[]>