refactor: 简化热词配置为豆包控制台 ID

- 移除本地热词列表配置，改为直接使用豆包控制台的热词表 ID
- 删除 internal/asr/hotwords.go（不再需要本地解析）
- 简化 client.go 逻辑，直接传递 boosting_table_id
- 移除 protocol.go 中的 boosting_table_name 字段
- 更新配置示例，添加控制台链接说明

使用方法：
1. 在豆包控制台创建热词表：https://console.volcengine.com/speech/hotword
2. 复制热词表 ID 到 config.yaml 的 boosting_table_id 字段

internal/asr/hotwords.go

@@ -1,107 +0,0 @@
-package asr
-
-import (
-	"crypto/sha256"
-	"encoding/hex"
-	"fmt"
-	"strconv"
-	"strings"
-	"unicode/utf8"
-)
-
-const (
-	// DefaultHotwordWeight is the default weight when not specified.
-	DefaultHotwordWeight = 4
-	// MaxHotwordWeight is the maximum allowed weight.
-	MaxHotwordWeight = 10
-	// MinHotwordWeight is the minimum allowed weight.
-	MinHotwordWeight = 1
-	// MaxHotwordLength is the maximum character count per hotword.
-	MaxHotwordLength = 10
-)
-
-// HotwordEntry represents a single hotword with its weight.
-type HotwordEntry struct {
-	Word   string
-	Weight int // 1-10, default 4
-}
-
-// ParseHotwords parses raw hotword strings from config.
-// Format: "word|weight" or "word" (default weight 4).
-// Returns error if any hotword is invalid.
-func ParseHotwords(raw []string) ([]HotwordEntry, error) {
-	if len(raw) == 0 {
-		return nil, nil
-	}
-
-	entries := make([]HotwordEntry, 0, len(raw))
-	for i, line := range raw {
-		line = strings.TrimSpace(line)
-		if line == "" {
-			continue
-		}
-
-		parts := strings.Split(line, "|")
-		word := strings.TrimSpace(parts[0])
-
-		// Validate word length
-		if utf8.RuneCountInString(word) > MaxHotwordLength {
-			return nil, fmt.Errorf("hotword %d: exceeds %d characters: %q", i+1, MaxHotwordLength, word)
-		}
-		if word == "" {
-			return nil, fmt.Errorf("hotword %d: empty word", i+1)
-		}
-
-		// Parse weight
-		weight := DefaultHotwordWeight
-		if len(parts) > 1 {
-			weightStr := strings.TrimSpace(parts[1])
-			if weightStr != "" {
-				w, err := strconv.Atoi(weightStr)
-				if err != nil {
-					return nil, fmt.Errorf("hotword %d: invalid weight %q: %w", i+1, weightStr, err)
-				}
-				if w < MinHotwordWeight || w > MaxHotwordWeight {
-					return nil, fmt.Errorf("hotword %d: weight %d out of range [%d, %d]", i+1, w, MinHotwordWeight, MaxHotwordWeight)
-				}
-				weight = w
-			}
-		}
-
-		entries = append(entries, HotwordEntry{
-			Word:   word,
-			Weight: weight,
-		})
-	}
-
-	return entries, nil
-}
-
-// FormatHotwordsTable generates Doubao-compatible hotword table content.
-// Format: each line "word|weight\n".
-func FormatHotwordsTable(entries []HotwordEntry) string {
-	if len(entries) == 0 {
-		return ""
-	}
-
-	var sb strings.Builder
-	for _, e := range entries {
-		sb.WriteString(e.Word)
-		sb.WriteString("|")
-		sb.WriteString(strconv.Itoa(e.Weight))
-		sb.WriteString("\n")
-	}
-	return sb.String()
-}
-
-// GenerateTableName generates a unique table name based on hotword content.
-// Uses SHA256 hash of the formatted table content (first 16 hex chars).
-func GenerateTableName(entries []HotwordEntry) string {
-	if len(entries) == 0 {
-		return ""
-	}
-
-	content := FormatHotwordsTable(entries)
-	hash := sha256.Sum256([]byte(content))
-	return "voicepaste_" + hex.EncodeToString(hash[:])[:16]
-}