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-tools/schema/tool_meta.schema.json

@@ -36,7 +36,7 @@
   ],
   "definitions": {
     "ToolKind": {
-      "description": "Categorizes what a tool does at a high level. Open set — consumers must tolerate unknown values (Rust deserializes them to `other` via `#[serde(other)]`). Known values: `read`, `edit`, `delete`, `list_dir`, `write`, `move`, `search`, `lsp`, `execute`, `plan`, `web_search`, `web_fetch`, `background_task_action`, `wait_tasks_action`, `kill_task_action`, `list`, `skill`, `memory_search`, `memory_get`, `task`, `enter_plan`, `exit_plan`, `ask_user`, `image_gen`, `video_gen`, `image_to_video`, `reference_to_video`, `deploy_app`, `search_tool`, `use_tool`, `monitor`, `goal_update`, `other`.",
+      "description": "Categorizes what a tool does at a high level. Open set — consumers must tolerate unknown values (Rust deserializes them to `other` via `#[serde(other)]`). Known values: `read`, `edit`, `delete`, `list_dir`, `write`, `move`, `search`, `lsp`, `execute`, `plan`, `web_search`, `web_fetch`, `background_task_action`, `wait_tasks_action`, `kill_task_action`, `list`, `skill`, `memory_search`, `memory_get`, `task`, `enter_plan`, `exit_plan`, `ask_user`, `deploy_app`, `search_tool`, `use_tool`, `monitor`, `goal_update`, `other`.",
       "type": "string"
     },
     "ToolNamespace": {