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/channel-plugin-guide.md

@@ -155,7 +155,7 @@ The key (`webhook`) becomes the config section name. The value points to your `B
 
 ```bash
 python -m pip install -e .
-nanobot plugins list      # verify "Webhook" shows as "plugin"
+nanobot plugins list      # verify the installed example plugin appears as "webhook"
 nanobot onboard           # auto-adds default config for detected plugins
 ```
 
@@ -552,7 +552,7 @@ If not overridden, the base class returns `{"enabled": false}`.
 git clone https://github.com/you/nanobot-channel-webhook
 cd nanobot-channel-webhook
 python -m pip install -e .
-nanobot plugins list    # should show "Webhook" as "plugin"
+nanobot plugins list    # should show the installed example plugin as "webhook"
 nanobot gateway         # test end-to-end
 ```
 
@@ -561,8 +561,8 @@ nanobot gateway         # test end-to-end
 ```bash
 $ nanobot plugins list
 
-  Name       Source    Enabled
-  telegram   builtin  yes
-  discord    builtin  no
-  webhook    plugin   yes
+  Name       Type      Enabled
+  discord    channel   no
+  telegram   channel   yes
+  webhook    channel   yes
 ```