fix(feishu): parse bot/v3/info top-level bot object for mention detection (#1189)

The legacy /open-apis/bot/v3/info endpoint returns the bot object at the
top level of the response, not inside "data" like newer Lark APIs. The
probe always failed to extract open_id, leaving botOpenID empty, which
made every group mention count as a bot mention — the bot replied to
messages mentioning other users even with requireMention enabled.

- Read top-level "bot" first, fall back to data.bot defensively
- Retry the startup probe with backoff to survive transient failures
- Fix test fixtures to match the real API response shape

Fixes #895

internal/channels/feishu/feishu.go

@@ -135,8 +135,10 @@ func (c *Channel) Start(ctx context.Context) error {
 	c.GroupHistory().StartFlusher()
 	slog.Info("starting feishu/lark bot")
 
-	// Probe bot identity
-	if err := c.probeBotInfo(ctx); err != nil {
+	// Probe bot identity. Without botOpenID, mention detection degrades to
+	// "any mention counts as bot mention" (see parseMessageEvent), so retry
+	// transient failures before giving up.
+	if err := c.probeBotInfoWithRetry(ctx, 3); err != nil {
 		slog.Warn("feishu bot probe failed (will continue)", "error", err)
 	} else {
 		slog.Info("feishu bot connected", "bot_open_id", c.botOpenID)
@@ -370,6 +372,25 @@ func (c *Channel) probeBotInfo(ctx context.Context) error {
 	return nil
 }
 
+// probeBotInfoWithRetry retries probeBotInfo with linear backoff to survive
+// transient startup failures (network blips, token service warm-up).
+func (c *Channel) probeBotInfoWithRetry(ctx context.Context, attempts int) error {
+	var err error
+	for i := 0; i < attempts; i++ {
+		if err = c.probeBotInfo(ctx); err == nil {
+			return nil
+		}
+		if i < attempts-1 {
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			case <-time.After(time.Duration(i+1) * 2 * time.Second):
+			}
+		}
+	}
+	return err
+}
+
 // --- Send helpers ---
 
 func (c *Channel) sendChunkedText(ctx context.Context, chatID, receiveIDType, text string, chunkLimit int, replyTargetID string) error {

internal/channels/feishu/larkclient.go

@@ -104,6 +104,9 @@ type apiResponse struct {
 	Code int             `json:"code"`
 	Msg  string          `json:"msg"`
 	Data json.RawMessage `json:"data"`
+	// Bot is only present on the legacy /open-apis/bot/v3/info endpoint,
+	// which returns the bot object at the top level instead of inside "data".
+	Bot json.RawMessage `json:"bot"`
 }
 
 // doJSON performs an authenticated JSON API call with auto token refresh.

internal/channels/feishu/larkclient_messaging.go

@@ -270,6 +270,9 @@ func (c *LarkClient) DeleteMessageReaction(ctx context.Context, messageID, react
 
 // GetBotInfo fetches the bot's identity from /open-apis/bot/v3/info.
 // Returns the bot's open_id which is needed for mention detection in groups.
+// This legacy endpoint returns the bot object at the TOP level of the
+// response ({"code":0,"msg":"ok","bot":{...}}), not inside "data" like
+// newer Lark APIs — read resp.Bot first, with a data.bot fallback.
 func (c *LarkClient) GetBotInfo(ctx context.Context) (string, error) {
 	resp, err := c.doJSON(ctx, "GET", "/open-apis/bot/v3/info", nil)
 	if err != nil {
@@ -278,15 +281,31 @@ func (c *LarkClient) GetBotInfo(ctx context.Context) (string, error) {
 	if resp.Code != 0 {
 		return "", fmt.Errorf("get bot info: code=%d msg=%s", resp.Code, resp.Msg)
 	}
-	var result struct {
-		Bot struct {
-			OpenID string `json:"open_id"`
-		} `json:"bot"`
+
+	var botInfo struct {
+		OpenID string `json:"open_id"`
 	}
-	if err := json.Unmarshal(resp.Data, &result); err != nil {
-		return "", fmt.Errorf("unmarshal response: %w", err)
+	if len(resp.Bot) > 0 {
+		if err := json.Unmarshal(resp.Bot, &botInfo); err != nil {
+			return "", fmt.Errorf("unmarshal bot info: %w", err)
+		}
+		return botInfo.OpenID, nil
 	}
-	return result.Bot.OpenID, nil
+
+	// Fallback: some deployments may wrap the bot object inside "data".
+	if len(resp.Data) > 0 {
+		var wrapped struct {
+			Bot struct {
+				OpenID string `json:"open_id"`
+			} `json:"bot"`
+		}
+		if err := json.Unmarshal(resp.Data, &wrapped); err != nil {
+			return "", fmt.Errorf("unmarshal bot info data: %w", err)
+		}
+		return wrapped.Bot.OpenID, nil
+	}
+
+	return "", fmt.Errorf("get bot info: response missing bot object")
 }
 
 // --- IM API: Chat Members ---

internal/channels/feishu/larkclient_messaging_extra_test.go

@@ -273,7 +273,9 @@ func TestDeleteMessageReaction_APIError(t *testing.T) {
 // --- GetBotInfo (returns open_id string) ---
 
 func TestGetBotInfo_Success(t *testing.T) {
-	srv := newSimpleMockServer(t, `{"code":0,"msg":"ok","data":{"bot":{"open_id":"ou_bot_123","app_name":"TestBot"}}}`)
+	// Real /open-apis/bot/v3/info responses put "bot" at the TOP level,
+	// not inside "data" (legacy API shape).
+	srv := newSimpleMockServer(t, `{"code":0,"msg":"ok","bot":{"open_id":"ou_bot_123","app_name":"TestBot"}}`)
 
 	c := NewLarkClient("app", "secret", srv.URL)
 	openID, err := c.GetBotInfo(context.Background())
@@ -285,6 +287,30 @@ func TestGetBotInfo_Success(t *testing.T) {
 	}
 }
 
+func TestGetBotInfo_DataWrappedFallback(t *testing.T) {
+	// Defensive fallback for deployments that wrap the bot object in "data".
+	srv := newSimpleMockServer(t, `{"code":0,"msg":"ok","data":{"bot":{"open_id":"ou_bot_456","app_name":"TestBot"}}}`)
+
+	c := NewLarkClient("app", "secret", srv.URL)
+	openID, err := c.GetBotInfo(context.Background())
+	if err != nil {
+		t.Fatalf("GetBotInfo error: %v", err)
+	}
+	if openID != "ou_bot_456" {
+		t.Errorf("open_id: got %q, want ou_bot_456", openID)
+	}
+}
+
+func TestGetBotInfo_MissingBotObject(t *testing.T) {
+	srv := newSimpleMockServer(t, `{"code":0,"msg":"ok"}`)
+
+	c := NewLarkClient("app", "secret", srv.URL)
+	_, err := c.GetBotInfo(context.Background())
+	if err == nil {
+		t.Fatal("expected error when response has no bot object")
+	}
+}
+
 func TestGetBotInfo_APIError(t *testing.T) {
 	srv := newSimpleMockServer(t, `{"code":10001,"msg":"forbidden","data":{}}`)