wire up identity agent, research tool, silence state

main.rs: create KratosClient, pass mistral+store to ToolRegistry,
build active_agents list for dynamic delegation.

conversations.rs: context_hint for new conversations, reset_all.
sdk/mod.rs: added kratos module.

src/sdk/mod.rs

@@ -1,3 +1,4 @@
 pub mod gitea;
+pub mod kratos;
 pub mod tokens;
 pub mod vault;