webui: add option for LLM title generation (#22265)

webui: add option for LLM title generation (#22265)

* webui: add LLM title generation option

* webui: use chat_template_kwargs for title gen + fix conversation check

* webui: capture firstUserMessage before async streamChatCompletion to fix race condition

* webui: extract LLM title generation into separate method

* webui: use constants and ChatService for LLM generated titles

* webui: rebuild static output

* webui: add LLM title generation setting to new settings location

* webui: use sendMessage in generateTitle

* webui: rebuild static output

* webui: fix formatting

* webui: configurable title prompt, remove think tag regexes, fix TS error

* webui: group title constants into TITLE object, use TruncatedText for CSS truncation and fix race condition

* webui: rebuild static output