M2 audit: excise managed connectors and xAI media-gen tools

Managed connectors (grok.com MCP admin) removed root-and-branch:
- The managed-MCP fetch/injection pipeline is gone, including the whole
  kigi-shell-session-support crate (managed-config fetch client, gateway
  tool catalog + dispatch, header injection, refresh task), reactive
  managed re-auth, mcp_doctor's grok.com-source discovery, and the
  [managed_mcps] config surface.
- TUI: the 'Managed by grok.com' section, connectors URL/deep-link,
  Action::OpenManagedConnectors, and session_team_id are gone. Local MCP
  management (list/toggle/add/remove/auth/tools) is fully intact.
- Kept as LOCAL policy: managed-settings.json MCP allow/deny enforcement,
  the multi-source local MCP merge, folder-trust gating. PluginOrigin
  Project/User labels kept (they tag locally discovered plugin dirs).

imagine/media-gen tools (xAI image/video generation) removed:
- image_gen, image_edit, video_gen, image_to_video, reference_to_video
  implementations, registrations, ToolKind/ToolInput/Output variants
  (serde-safe), config plumbing end to end, ZDR video machinery,
  /imagine + /imagine-video commands and guidance text, the bundled
  imagine skill (added to legacy cleanup so user installs delete it),
  and the media-gen render path.
- Kept: image INPUT (paste/attach, [Image #N] meta, pdf/image fetch,
  clipboard wrap), generic media-ref rendering, and the generic tool
  401-retry machinery (tests renamed, assertions unweakened).
- deploy_app stays: it is a permanently-disabled local stub deploying
  nowhere.

121 files changed, 8 deleted. Gates: workspace check/clippy 0/0, fmt,
deny ok; suites green (tools 2554, shell 4862, tui 6608, workspace
1042). Remaining grok.com strings live only in the auth-method ids and
changelog archives (§9/M3 sweep).

crates/codegen/kigi-shell/src/agent/app.rs

@@ -917,15 +917,6 @@ pub async fn run_leader(
                         }
                         ConfigUpdate::AuthCleared => {
                             auth_manager_for_config.clear_in_memory();
-                            let line = internal_reload_request_line(
-                                "config-auth-cleared",
-                                "x.ai/internal/auth_cleared",
-                                serde_json::json!({}),
-                            );
-                            let mut tx = acp_tx_for_config.lock().await;
-                            if let Err(e) = tx.write_all(line.as_bytes()).await {
-                                warn!(error = %e, "failed to inject auth-cleared cleanup into ACP stream");
-                            }
                             models_manager_for_config.on_auth_changed().await;
                             kigi_log::unified_log::warn(
                                 "auth cleared from disk",
@@ -1144,14 +1135,6 @@ mod tests {
         );
         let msg: serde_json::Value = serde_json::from_str(line.trim_end()).unwrap();
         assert_eq!(msg["params"]["cwd"], "/repo/x");
-
-        let line = internal_reload_request_line(
-            "config-auth-cleared",
-            "x.ai/internal/auth_cleared",
-            serde_json::json!({}),
-        );
-        let msg: serde_json::Value = serde_json::from_str(line.trim_end()).unwrap();
-        assert_eq!(msg["method"], "_x.ai/internal/auth_cleared");
     }
 
     #[tokio::test]