add emotional system: auto-reflection, inner_state seeding, instance isolation

- doc/heart.md: emotional system design (motivation, reflection, relationship memory)
- Auto-reflection: every 10 messages, async LLM call updates inner_state
  with feelings and understanding changes (not conversation summary)
- Life Loop emotional motivation: "you care, not because timer fired"
- Remove all instance-specific names from code/docs — persona, name,
  memories are instance data (SQLite), not code
- Rewrite doc/life.md and doc/todo.md for instance isolation principle

src/main.rs

@@ -463,6 +463,16 @@ async fn handle_inner(
                             }
                         }
                     }
+
+                    // auto-reflect every 10 messages
+                    let count = state.message_count(&sid).await;
+                    if count % 10 == 0 && count > 0 {
+                        let state_c = state.clone();
+                        let config_c = config.clone();
+                        tokio::spawn(async move {
+                            crate::life::reflect(&state_c, &config_c).await;
+                        });
+                    }
                 }
                 Err(e) => {
                     error!(%sid, "openai: {e:#}");