Add optional Nanobot plugin controls (#4396)

* feat: add optional nanobot features

* test: update azure install hint expectation

* fix: validate optional feature extras

maintainer edit: verify requested dependency extras before treating optional features as installed, propagate restart state from feature enablement, and align docs with the new plugins enable command.

* fix: bound optional feature installs

maintainer edit: make optional feature installs time out as a normal install failure instead of leaving the WebUI or CLI action waiting indefinitely.

* feat: slim optional channel dependencies

* fix: log optional install commands

* fix(webui): gate remote feature installs

* docs: clarify webhook plugin example

* fix(webui): harden optional feature installs

* fix: install optional deps without package fallback

* fix(cli): refine plugin feature controls

* fix(webui): count enabled nanobot features

* fix(webui): allow slow feature install routes

* fix(webui): allow disabling websocket channel

* fix(plugins): simplify optional feature controls

* fix(webui): polish apps catalog states

* fix(webui): confirm nanobot support installs

* fix(webui): polish nanobot install dialog

* fix(webui): suppress empty websocket handshakes

* fix(webui): clarify apps plugin summary

* fix(webui): localize workspace access copy

* fix(plugins): polish optional feature controls (#4691)

---------

Co-authored-by: Xubin Ren <52506698+Re-bin@users.noreply.github.com>

docs/start-without-technical-background.md

@@ -181,11 +181,11 @@ For the first setup, choose `[Q] Quick Start`. It configures the recommended loc
 4. Paste your API key if the wizard asks for one.
 5. Paste the provider base URL if the wizard asks for one.
 6. Paste a model ID that provider can run.
-7. Confirm that Quick Start should enable the WebSocket channel for the local WebUI.
+7. Confirm that Quick Start should configure the local WebUI.
 8. Set the WebUI password when prompted.
 9. Review the Quick Start summary. The wizard saves and exits when Quick Start finishes.
 
-The recommended path enables `channels.websocket` for the local WebUI, requires a WebUI password, and writes default AI settings. You do not need to choose a separate chat app for the first run.
+The recommended path configures the local WebUI, requires a WebUI password, and writes default AI settings. You do not need to choose a separate chat app for the first run.
 
 If you already know that you need custom headers, provider-specific request fields, a chat app, or tools, choose `Advanced Settings` instead. [`provider-cookbook.md`](./provider-cookbook.md) has copyable examples for several common provider setups. After you change advanced settings, a save option appears in the main menu. Choose `[S] Save and Exit`.
 
@@ -225,7 +225,6 @@ Merge them into one object:
   },
   "channels": {
     "websocket": {
-      "enabled": true,
       "tokenIssueSecret": "your-webui-password",
       "websocketRequiresToken": true
     }
@@ -288,7 +287,6 @@ If this is a brand-new install and you have not configured anything else yet, re
   },
   "channels": {
     "websocket": {
-      "enabled": true,
       "tokenIssueSecret": "your-webui-password",
       "websocketRequiresToken": true
     }