feat(chat): replace built-in chat with LibreChat SSO integration

Replaces the custom chat page with an external LibreChat instance that
shares Keycloak SSO for seamless auto-login. Removes Tools and Knowledge
Base pages as these are now handled by LibreChat's built-in capabilities.

- Add LibreChat service to docker-compose with Ollama backend config
- Add Keycloak OIDC client (certifai-librechat) with prompt=none for
  silent SSO
- Create librechat.yaml with CERTifAI branding, Ollama endpoint, and
  custom page title/logo
- Change sidebar Chat link to external URL (opens LibreChat in new tab)
- Remove chat page, tools page, knowledge base page and all related
  components (chat_sidebar, chat_bubble, chat_input_bar, etc.)
- Remove tool_card, file_row components and tool/knowledge models
- Remove chat_stream SSE handler (no longer needed)
- Clean up i18n files: remove chat, tools, knowledge sections
- Dashboard article summarization via Ollama remains intact

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/mod.rs

@@ -1,14 +1,7 @@
 mod app_shell;
 mod article_detail;
 mod card;
-mod chat_action_bar;
-mod chat_bubble;
-mod chat_input_bar;
-mod chat_message_list;
-mod chat_model_selector;
-mod chat_sidebar;
 mod dashboard_sidebar;
-mod file_row;
 mod login;
 mod member_row;
 pub mod news_card;
@@ -16,23 +9,14 @@ mod page_header;
 mod pricing_card;
 pub mod sidebar;
 pub mod sub_nav;
-mod tool_card;
 
 pub use app_shell::*;
 pub use article_detail::*;
 pub use card::*;
-pub use chat_action_bar::*;
-pub use chat_bubble::*;
-pub use chat_input_bar::*;
-pub use chat_message_list::*;
-pub use chat_model_selector::*;
-pub use chat_sidebar::*;
 pub use dashboard_sidebar::*;
-pub use file_row::*;
 pub use login::*;
 pub use member_row::*;
 pub use news_card::*;
 pub use page_header::*;
 pub use pricing_card::*;
 pub use sub_nav::*;
-pub use tool_card::*;