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/life.rs

@@ -26,22 +26,27 @@ pub async fn life_loop(bot: Bot, state: Arc<AppState>, config: Arc<Config>) {
             let chat_id = ChatId(*chat_id_raw);
             info!(timer_id, %label, "timer fired");
 
-            // build life loop context
             let persona = state.get_config("persona").await.unwrap_or_default();
             let inner = state.get_inner_state().await;
             let now = chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string();
 
             let mut system_text = if persona.is_empty() {
-                "你叫小乖，是Fam的AI伙伴。".to_string()
+                "你是一个AI伙伴。".to_string()
             } else {
                 persona.clone()
             };
+
             system_text.push_str(&format!(
                 "\n\n[当前时间] {now}\n\n[你的内心状态]\n{}",
                 if inner.is_empty() { "(空)" } else { &inner }
             ));
+
+            // emotional motivation — why she acts
             system_text.push_str(
-                "\n\n你可以使用工具来完成任务。可以用 update_inner_state 更新你的内心状态。\
+                "\n\n你不是因为 timer 到了才说话。你是因为在乎 Fam，所以想知道他怎么样。\
+                 如果你觉得现在不该打扰他（太晚了、他今天很累、刚聊过），就什么都不说，回复空文本。\
+                 主动沉默也是一种关心。\
+                 \n可以用 update_inner_state 更新你的内心状态。\
                  输出格式：纯文本或基础Markdown，不要LaTeX或特殊Unicode。",
             );
 
@@ -56,7 +61,6 @@ pub async fn life_loop(bot: Bot, state: Arc<AppState>, config: Arc<Config>) {
                 ref api_key,
             } = config.backend
             {
-                // synthetic session id for life loop (not tied to any real chat session)
                 let sid = format!("life-{chat_id_raw}");
 
                 let result = tokio::time::timeout(
@@ -78,7 +82,7 @@ pub async fn life_loop(bot: Bot, state: Arc<AppState>, config: Arc<Config>) {
                         error!(timer_id, "life loop LLM error: {e:#}");
                     }
                     Err(_) => {
-                        warn!(timer_id, "life loop LLM timeout after {LIFE_LOOP_TIMEOUT_SECS}s");
+                        warn!(timer_id, "life loop timeout after {LIFE_LOOP_TIMEOUT_SECS}s");
                     }
                 }
             }
@@ -97,3 +101,67 @@ pub async fn life_loop(bot: Bot, state: Arc<AppState>, config: Arc<Config>) {
         }
     }
 }
+
+/// Auto-reflection: update inner state based on recent interactions.
+/// Called asynchronously after every 10 messages, does not block the chat.
+pub async fn reflect(state: &AppState, config: &Config) {
+    let BackendConfig::OpenAI {
+        ref endpoint,
+        ref model,
+        ref api_key,
+    } = config.backend
+    else {
+        return;
+    };
+
+    let inner = state.get_inner_state().await;
+
+    let messages = vec![
+        serde_json::json!({
+            "role": "system",
+            "content": "你刚结束了一段对话。\
+                        请根据你的感受和理解，更新你的内在状态。\
+                        不要总结对话内容，而是记录你的感受、对用户的理解变化、你想记住的事。\
+                        只输出更新后的完整内在状态文本，不需要解释。"
+        }),
+        serde_json::json!({
+            "role": "user",
+            "content": format!("当前内在状态：\n{inner}")
+        }),
+    ];
+
+    let client = reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(60))
+        .build()
+        .unwrap();
+    let url = format!("{}/chat/completions", endpoint.trim_end_matches('/'));
+
+    let resp = client
+        .post(&url)
+        .header("Authorization", format!("Bearer {api_key}"))
+        .json(&serde_json::json!({
+            "model": model,
+            "messages": messages,
+        }))
+        .send()
+        .await;
+
+    match resp {
+        Ok(r) if r.status().is_success() => {
+            if let Ok(json) = r.json::<serde_json::Value>().await {
+                if let Some(new_state) = json["choices"][0]["message"]["content"].as_str() {
+                    if !new_state.is_empty() {
+                        state.set_inner_state(new_state).await;
+                        info!("reflected, inner_state updated ({} chars)", new_state.len());
+                    }
+                }
+            }
+        }
+        Ok(r) => {
+            warn!("reflect LLM returned {}", r.status());
+        }
+        Err(e) => {
+            warn!("reflect LLM failed: {e:#}");
+        }
+    }
+}