feat(ai): improve runtime capability reporting and context settings

Add explicit chat capability tracking, expose formatted runtime capabilities
in the info command, and support a max context size option for user AI settings.

Also update Ollama base URL resolution to use OLLAMA_ADDRESS and simplify
provider chat command execution.

locales/ua.json

@@ -45,9 +45,8 @@
   "runtimeCapabilitiesLabelText": "можливості",
   "runtimeExternalLabelText": "зовнішній",
   "infoAiBlockLabelText": "AI",
-  "infoSupportedProvidersLabelText": "підтримувані провайдери",
+  "infoSupportedProvidersLabelText": "провайдери",
   "infoToolsBlockLabelText": "інструменти",
-  "infoCountLabelText": "кількість",
   "infoCommandsBlockLabelText": "команди",
   "infoPublicLabelText": "публічні",
   "infoPrivateLabelText": "приватні",