refactor: move bot_name from agents.defaults to per-channel config

Move bot_name to TelegramConfig and DingTalkConfig so each channel
can independently configure its display name, as suggested in review.

- Remove BotName from AgentDefaults
- Add BotName to TelegramConfig (env: PICOCLAW_CHANNELS_TELEGRAM_BOT_NAME)
- Add BotName to DingTalkConfig (env: PICOCLAW_CHANNELS_DINGTALK_BOT_NAME)
- Update telegram_commands.go to read from channel config
- Update dingtalk.go to read from its own config (remove botName param)
- Update manager.go to match new DingTalk constructor signature

pkg/channels/dingtalk.go

@@ -32,11 +32,12 @@ type DingTalkChannel struct {
 }
 
 // NewDingTalkChannel creates a new DingTalk channel instance
-func NewDingTalkChannel(cfg config.DingTalkConfig, messageBus *bus.MessageBus, botName string) (*DingTalkChannel, error) {
+func NewDingTalkChannel(cfg config.DingTalkConfig, messageBus *bus.MessageBus) (*DingTalkChannel, error) {
 	if cfg.ClientID == "" || cfg.ClientSecret == "" {
 		return nil, fmt.Errorf("dingtalk client_id and client_secret are required")
 	}
 
+	botName := cfg.BotName
 	if botName == "" {
 		botName = "PicoClaw"
 	}

pkg/channels/manager.go

@@ -126,7 +126,7 @@ func (m *Manager) initChannels() error {
 
 	if m.config.Channels.DingTalk.Enabled && m.config.Channels.DingTalk.ClientID != "" {
 		logger.DebugC("channels", "Attempting to initialize DingTalk channel")
-		dingtalk, err := NewDingTalkChannel(m.config.Channels.DingTalk, m.bus, m.config.Agents.Defaults.BotName)
+		dingtalk, err := NewDingTalkChannel(m.config.Channels.DingTalk, m.bus)
 		if err != nil {
 			logger.ErrorCF("channels", "Failed to initialize DingTalk channel", map[string]interface{}{
 				"error": err.Error(),

pkg/channels/telegram_commands.go

@@ -52,7 +52,7 @@ func (c *cmd) Help(ctx context.Context, message telego.Message) error {
 }
 
 func (c *cmd) Start(ctx context.Context, message telego.Message) error {
-	botName := c.config.Agents.Defaults.BotName
+	botName := c.config.Channels.Telegram.BotName
 	if botName == "" {
 		botName = "PicoClaw"
 	}

pkg/config/config.go

@@ -66,7 +66,6 @@ type AgentDefaults struct {
 	MaxTokens           int     `json:"max_tokens" env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOKENS"`
 	Temperature         float64 `json:"temperature" env:"PICOCLAW_AGENTS_DEFAULTS_TEMPERATURE"`
 	MaxToolIterations   int     `json:"max_tool_iterations" env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOOL_ITERATIONS"`
-	BotName             string  `json:"bot_name" env:"PICOCLAW_AGENTS_DEFAULTS_BOT_NAME"`
 }
 
 type ChannelsConfig struct {
@@ -92,6 +91,7 @@ type TelegramConfig struct {
 	Enabled   bool                `json:"enabled" env:"PICOCLAW_CHANNELS_TELEGRAM_ENABLED"`
 	Token     string              `json:"token" env:"PICOCLAW_CHANNELS_TELEGRAM_TOKEN"`
 	Proxy     string              `json:"proxy" env:"PICOCLAW_CHANNELS_TELEGRAM_PROXY"`
+	BotName   string              `json:"bot_name" env:"PICOCLAW_CHANNELS_TELEGRAM_BOT_NAME"`
 	AllowFrom FlexibleStringSlice `json:"allow_from" env:"PICOCLAW_CHANNELS_TELEGRAM_ALLOW_FROM"`
 }
 
@@ -128,6 +128,7 @@ type DingTalkConfig struct {
 	Enabled      bool                `json:"enabled" env:"PICOCLAW_CHANNELS_DINGTALK_ENABLED"`
 	ClientID     string              `json:"client_id" env:"PICOCLAW_CHANNELS_DINGTALK_CLIENT_ID"`
 	ClientSecret string              `json:"client_secret" env:"PICOCLAW_CHANNELS_DINGTALK_CLIENT_SECRET"`
+	BotName      string              `json:"bot_name" env:"PICOCLAW_CHANNELS_DINGTALK_BOT_NAME"`
 	AllowFrom    FlexibleStringSlice `json:"allow_from" env:"PICOCLAW_CHANNELS_DINGTALK_ALLOW_FROM"`
 }
 
@@ -227,7 +228,6 @@ func DefaultConfig() *Config {
 				MaxTokens:           8192,
 				Temperature:         0.7,
 				MaxToolIterations:   20,
-				BotName:             "PicoClaw",
 			},
 		},
 		Channels: ChannelsConfig{
@@ -239,6 +239,7 @@ func DefaultConfig() *Config {
 			Telegram: TelegramConfig{
 				Enabled:   false,
 				Token:     "",
+				BotName:   "PicoClaw",
 				AllowFrom: FlexibleStringSlice{},
 			},
 			Feishu: FeishuConfig{
@@ -270,6 +271,7 @@ func DefaultConfig() *Config {
 				Enabled:      false,
 				ClientID:     "",
 				ClientSecret: "",
+				BotName:      "PicoClaw",
 				AllowFrom:    FlexibleStringSlice{},
 			},
 			Slack: SlackConfig{