feat: 添加 Token 费用估算与自定义忽略规则

- 在 LLM 客户端中捕获流式响应的 Token 使用量
- 内置多模型官方定价表，支持自定义输入/输出单价覆盖
- 新增 `--price-input` 和 `--price-output` 配置项
- 支持通过 `.airignore` 文件自定义排除评审文件
- 更新中英日文文档，补充费用估算与忽略规则说明

internal/git/diff.go

@@ -43,6 +43,9 @@ func GetDiff(ctx context.Context, args ...string) (string, error) {
 		return "", ErrNotGitRepo
 	}
 
+	repoRoot, _ := GetRepoRoot(ctx)
+	customIgnores := LoadAirIgnore(repoRoot)
+
 	var cmdArgs []string
 	if len(args) == 0 {
 		// 1. 默认先提取暂存区代码 (准备 commit 的代码)
@@ -51,7 +54,7 @@ func GetDiff(ctx context.Context, args ...string) (string, error) {
 			return "", err
 		}
 		if strings.TrimSpace(stagedDiff) != "" {
-			return truncateDiffIfNeeded(FilterDiff(stagedDiff)), nil
+			return truncateDiffIfNeeded(FilterDiff(stagedDiff, customIgnores...)), nil
 		}
 		// 2. 如果暂存区为空，回退提取工作区未暂存的修改
 		cmdArgs = []string{}
@@ -64,7 +67,7 @@ func GetDiff(ctx context.Context, args ...string) (string, error) {
 		return "", err
 	}
 
-	filteredDiff := FilterDiff(rawDiff)
+	filteredDiff := FilterDiff(rawDiff, customIgnores...)
 	if strings.TrimSpace(filteredDiff) == "" {
 		return "", ErrEmptyDiff
 	}

internal/git/filter.go

@@ -1,13 +1,14 @@
 package git
 
 import (
+	"bufio"
+	"os"
 	"path/filepath"
-	"regexp"
 	"strings"
 )
 
 // 默认需要忽略的文件名与后缀列表
-var ignoredPatterns = []string{
+var defaultIgnoredPatterns = []string{
 	// 依赖与锁文件
 	"go.sum",
 	"package-lock.json",
@@ -36,19 +37,45 @@ var ignoredPatterns = []string{
 	"*.pdf",
 }
 
-// isIgnoredFile 判断文件路径是否应该在 Code Review 中被忽略
-func isIgnoredFile(filePath string) bool {
-	cleanPath := filepath.ToSlash(filePath)
+// LoadAirIgnore 从仓库根目录加载 .airignore 文件中的自定义忽略规则
+func LoadAirIgnore(repoRoot string) []string {
+	if repoRoot == "" {
+		return nil
+	}
+	ignoreFile := filepath.Join(repoRoot, ".airignore")
+	file, err := os.Open(ignoreFile)
+	if err != nil {
+		return nil
+	}
+	defer file.Close()
+
+	var patterns []string
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		trimmed := strings.TrimSpace(scanner.Text())
+		if trimmed == "" || strings.HasPrefix(trimmed, "#") {
+			continue
+		}
+		patterns = append(patterns, trimmed)
+	}
+	return patterns
+}
+
+// isIgnoredFile 判断文件路径是否命中忽略规则（内置规则 + 用户自定义规则）
+func isIgnoredFile(filePath string, customPatterns []string) bool {
+	cleanPath := filepath.ToSlash(strings.TrimSpace(filePath))
 	baseName := filepath.Base(cleanPath)
 
-	for _, pattern := range ignoredPatterns {
-		// 精确匹配文件名（如 go.sum）
-		if pattern == baseName {
+	// 1. 先匹配用户自定义规则 (.airignore)
+	for _, pattern := range customPatterns {
+		if matchPattern(pattern, cleanPath, baseName) {
 			return true
 		}
+	}
 
-		// 通配符匹配（如 *.pb.go）
-		if matched, _ := filepath.Match(pattern, baseName); matched {
+	// 2. 再匹配内置默认规则
+	for _, pattern := range defaultIgnoredPatterns {
+		if matchPattern(pattern, cleanPath, baseName) {
 			return true
 		}
 	}
@@ -56,10 +83,41 @@ func isIgnoredFile(filePath string) bool {
 	return false
 }
 
-var diffHeaderRegex = regexp.MustCompile(`(?m)^diff --git a/(.*?) b/(.*?)$`)
+// matchPattern 单条规则智能匹配（支持目录/、通配符*、精确匹配）
+func matchPattern(pattern, cleanPath, baseName string) bool {
+	pattern = filepath.ToSlash(strings.TrimSpace(pattern))
+	if pattern == "" {
+		return false
+	}
 
-// FilterDiff 过滤掉 diff 中无意义的锁文件和自动生成文件的区块
-func FilterDiff(rawDiff string) string {
+	// 目录规则：如 "docs/" 或 "vendor/"
+	if strings.HasSuffix(pattern, "/") {
+		dirPrefix := strings.TrimSuffix(pattern, "/")
+		if strings.HasPrefix(cleanPath, dirPrefix+"/") || cleanPath == dirPrefix {
+			return true
+		}
+	}
+
+	// 精确匹配文件名或相对路径
+	if pattern == baseName || pattern == cleanPath {
+		return true
+	}
+
+	// 通配符匹配文件名（如 *.pb.go）
+	if matched, _ := filepath.Match(pattern, baseName); matched {
+		return true
+	}
+
+	// 通配符匹配全路径（如 mock/*.go）
+	if matched, _ := filepath.Match(pattern, cleanPath); matched {
+		return true
+	}
+
+	return false
+}
+
+// FilterDiff 过滤掉 diff 中命中忽略规则（如锁文件、生成的代码、.airignore 排除项）的文件区块
+func FilterDiff(rawDiff string, customPatterns ...string) string {
 	if strings.TrimSpace(rawDiff) == "" {
 		return ""
 	}
@@ -85,7 +143,7 @@ func FilterDiff(rawDiff string) string {
 		parts := strings.Fields(firstLine)
 		if len(parts) >= 2 {
 			filePath := strings.TrimPrefix(parts[1], "b/")
-			if isIgnoredFile(filePath) {
+			if isIgnoredFile(filePath, customPatterns) {
 				continue // 命中忽略规则，跳过这个文件的 diff
 			}
 		}

internal/git/filter_test.go

@@ -0,0 +1,112 @@
+package git
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestIsIgnoredFile(t *testing.T) {
+	customPatterns := []string{
+		"docs/",
+		"tests/mock/*.json",
+		"secrets.env",
+	}
+
+	tests := []struct {
+		filePath string
+		expected bool
+	}{
+		// 默认内置忽略规则
+		{"go.sum", true},
+		{"package-lock.json", true},
+		{"api/user.pb.go", true},
+		{"web/dist/app.min.js", true},
+		{"assets/logo.png", true},
+
+		// 用户自定义 .airignore 规则
+		{"docs/readme.md", true},
+		{"docs/api/v1.md", true},
+		{"tests/mock/user.json", true},
+		{"secrets.env", true},
+
+		// 不应被忽略的正常业务代码
+		{"cmd/root.go", false},
+		{"internal/service/user.go", false},
+		{"pkg/utils/helper.go", false},
+	}
+
+	for _, tt := range tests {
+		got := isIgnoredFile(tt.filePath, customPatterns)
+		if got != tt.expected {
+			t.Errorf("isIgnoredFile(%q) = %v, expected %v", tt.filePath, got, tt.expected)
+		}
+	}
+}
+
+func TestLoadAirIgnore(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "git-air-test-*")
+	if err != nil {
+		t.Fatalf("创建临时目录失败: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	content := `# 忽略文档
+			docs/
+			# 忽略临时文件
+			*.tmp
+			*.log
+		`
+	ignoreFile := filepath.Join(tempDir, ".airignore")
+	if err := os.WriteFile(ignoreFile, []byte(content), 0644); err != nil {
+		t.Fatalf("写入 .airignore 失败: %v", err)
+	}
+
+	patterns := LoadAirIgnore(tempDir)
+	expected := []string{"docs/", "*.tmp", "*.log"}
+
+	if len(patterns) != len(expected) {
+		t.Fatalf("LoadAirIgnore 返回数量不符: got %v, expected %v", patterns, expected)
+	}
+
+	for i, p := range patterns {
+		if p != expected[i] {
+			t.Errorf("Pattern[%d] = %q, expected %q", i, p, expected[i])
+		}
+	}
+}
+
+func TestFilterDiff(t *testing.T) {
+	rawDiff := `diff --git a/go.sum b/go.sum
+			index 111..222 100644
+			--- a/go.sum
+			+++ b/go.sum
+			@@ -1 +1 @@
+			+some-package v1.0.0 h1:...
+			diff --git a/internal/service/user.go b/internal/service/user.go
+			index 333..444 100644
+			--- a/internal/service/user.go
+			+++ b/internal/service/user.go
+			@@ -1 +1 @@
+			+func HandleUser() {}
+			diff --git a/docs/spec.md b/docs/spec.md
+			index 555..666 100644
+			--- a/docs/spec.md
+			+++ b/docs/spec.md
+			@@ -1 +1 @@
+			+# API Spec
+			`
+	customPatterns := []string{"docs/"}
+	filtered := FilterDiff(rawDiff, customPatterns...)
+
+	if strings.Contains(filtered, "go.sum") {
+		t.Errorf("FilterDiff 应当过滤掉 go.sum")
+	}
+	if strings.Contains(filtered, "docs/spec.md") {
+		t.Errorf("FilterDiff 应当过滤掉 docs/spec.md")
+	}
+	if !strings.Contains(filtered, "internal/service/user.go") {
+		t.Errorf("FilterDiff 应当保留正常的业务代码 internal/service/user.go")
+	}
+}