feat: 实现本地热词管理，移除平台绑定

- 使用 corpus.context 参数直接传递热词列表（豆包文档支持）
- 移除 boosting_table_id 配置，避免绑定火山引擎控制台
- 实现 BuildHotwordsContext 函数，将本地热词转换为 JSON 格式
- 热词配置完全本地化，便于迁移到其他 ASR 平台

配置示例：
  hotwords:
    - 张三
    - 李四
    - VoicePaste

程序自动转换为豆包 API 要求的格式：
{"hotwords":[{"word":"张三"},{"word":"李四"},{"word":"VoicePaste"}]}

internal/asr/client.go

@@ -20,10 +20,10 @@ const (
 
 // Config holds Doubao ASR connection parameters.
 type Config struct {
-	AppID            string
-	AccessToken      string
-	ResourceID       string
-	BoostingTableID  string // 热词表 ID（从控制台创建）
+	AppID       string
+	AccessToken string
+	ResourceID  string
+	Hotwords    []string // 本地热词列表
 }
 
 // Client manages a single ASR session with Doubao.
@@ -58,6 +58,17 @@ func Dial(cfg Config, resultCh chan<- wsMsg.ServerMsg) (*Client, error) {
 		closeCh: make(chan struct{}),
 		log:     slog.With("conn_id", connID),
 	}
+	// Build corpus configuration
+	var corpus *Corpus
+	if len(cfg.Hotwords) > 0 {
+		contextJSON, err := BuildHotwordsContext(cfg.Hotwords)
+		if err != nil {
+			slog.Warn("failed to build hotwords context, skipping", "err", err)
+		} else {
+			corpus = &Corpus{Context: contextJSON}
+			slog.Info("hotwords enabled", "count", len(cfg.Hotwords))
+		}
+	}
 	// Send FullClientRequest
 	req := &FullClientRequest{
 		User: UserMeta{UID: connID},
@@ -69,15 +80,15 @@ func Dial(cfg Config, resultCh chan<- wsMsg.ServerMsg) (*Client, error) {
 			Channel: 1,
 		},
 		Request: RequestMeta{
-			ModelName:         "seedasr-2.0",
-			EnableITN:         true,
-			EnablePUNC:        true,
-			EnableDDC:         true,
-			ShowUtterances:    true,
-			ResultType:        "full",
-			EnableNonstream:   true,
-			EndWindowSize:     800,
-			BoostingTableID:   cfg.BoostingTableID,
+			ModelName:       "seedasr-2.0",
+			EnableITN:       true,
+			EnablePUNC:      true,
+			EnableDDC:       true,
+			ShowUtterances:  true,
+			ResultType:      "full",
+			EnableNonstream: true,
+			EndWindowSize:   800,
+			Corpus:          corpus,
 		},
 	}
 	data, err := EncodeFullClientRequest(req)

internal/asr/hotwords.go

@@ -0,0 +1,43 @@
+package asr
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// HotwordEntry represents a single hotword for context JSON.
+type HotwordEntry struct {
+	Word string `json:"word"`
+}
+
+// HotwordsContext represents the context JSON structure for hotwords.
+type HotwordsContext struct {
+	Hotwords []HotwordEntry `json:"hotwords"`
+}
+
+// BuildHotwordsContext converts a list of hotword strings to context JSON string.
+// Returns empty string if hotwords list is empty.
+func BuildHotwordsContext(hotwords []string) (string, error) {
+	if len(hotwords) == 0 {
+		return "", nil
+	}
+
+	entries := make([]HotwordEntry, 0, len(hotwords))
+	for _, word := range hotwords {
+		if word != "" {
+			entries = append(entries, HotwordEntry{Word: word})
+		}
+	}
+
+	if len(entries) == 0 {
+		return "", nil
+	}
+
+	ctx := HotwordsContext{Hotwords: entries}
+	data, err := json.Marshal(ctx)
+	if err != nil {
+		return "", fmt.Errorf("marshal hotwords context: %w", err)
+	}
+
+	return string(data), nil
+}

internal/asr/protocol.go

@@ -103,16 +103,21 @@ type AudioMeta struct {
 	Channel int    `json:"channel"`
 }
 
+// Corpus holds hotwords and context configuration.
+type Corpus struct {
+	Context string `json:"context,omitempty"` // 热词直传 JSON
+}
+
 type RequestMeta struct {
-	ModelName        string `json:"model_name"`
-	EnableITN        bool   `json:"enable_itn"`
-	EnablePUNC       bool   `json:"enable_punc"`
-	EnableDDC        bool   `json:"enable_ddc"`
-	ShowUtterances   bool   `json:"show_utterances"`
-	ResultType       string `json:"result_type,omitempty"`
-	EnableNonstream  bool   `json:"enable_nonstream,omitempty"`
-	EndWindowSize    int    `json:"end_window_size,omitempty"`
-	BoostingTableID  string `json:"boosting_table_id,omitempty"` // 热词表 ID
+	ModelName        string  `json:"model_name"`
+	EnableITN        bool    `json:"enable_itn"`
+	EnablePUNC       bool    `json:"enable_punc"`
+	EnableDDC        bool    `json:"enable_ddc"`
+	ShowUtterances   bool    `json:"show_utterances"`
+	ResultType       string  `json:"result_type,omitempty"`
+	EnableNonstream  bool    `json:"enable_nonstream,omitempty"`
+	EndWindowSize    int     `json:"end_window_size,omitempty"`
+	Corpus           *Corpus `json:"corpus,omitempty"` // 语料/热词配置
 }
 // EncodeFullClientRequest builds the binary message for the initial handshake.
 // nostream mode: header(4) + payload_size(4) + gzip(json)