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/infrastructure/mod.rs

@@ -12,8 +12,6 @@ mod auth;
 #[cfg(feature = "server")]
 mod auth_middleware;
 #[cfg(feature = "server")]
-mod chat_stream;
-#[cfg(feature = "server")]
 pub mod config;
 #[cfg(feature = "server")]
 pub mod database;
@@ -33,8 +31,6 @@ pub use auth::*;
 #[cfg(feature = "server")]
 pub use auth_middleware::*;
 #[cfg(feature = "server")]
-pub use chat_stream::*;
-#[cfg(feature = "server")]
 pub use error::*;
 #[cfg(feature = "server")]
 pub use server::*;