Unconscious agents: persistent AutoAgent, shared Agent Arc for UI

- AutoAgent stored on UnconsciousAgent, swapped out for runs, restored
  on completion (same pattern as subconscious agents)
- Agent Arc created before spawn and stored on UnconsciousAgent so
  the TUI can lock it to read conversation context live
- run_shared() method on AutoAgent for running with a pre-created Agent
- Default tools: memory_tools (not memory_and_journal_tools)
- trigger/spawn_agent made async for Agent::new()

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/mind/mod.rs

@@ -552,7 +552,7 @@ impl Mind {
                 if unc_handle.as_ref().map_or(true, |h| h.is_finished()) {
                     let unc = self.unconscious.clone();
                     unc_handle = Some(tokio::spawn(async move {
-                        unc.lock().await.trigger();
+                        unc.lock().await.trigger().await;
                     }));
                 }
             }