refactor: 按模块重构项目结构

- 删除 vars 全局状态，按职责拆分 internal/ 包：scanner/probe/classify/organize/mover/store/digest
- 数据驱动归类规则替代图片/视频重复分支，store 改为结构体实例
- build.sh 按系统类型编译：Windows 用 upx 压缩，macOS/Linux 不压缩
- 忽略目录拆分：图片_已忽略 / 视频_已忽略
- 输出构建产物加入 .gitignore

internal/classify/classify.go

@@ -0,0 +1,72 @@
+// Package classify 提供纯函数的分辨率归类规则，不依赖任何状态。
+package classify
+
+import "strings"
+
+// Orientation 画面方向
+type Orientation int
+
+const (
+	OrientationSquare Orientation = iota
+	OrientationHorizontal
+	OrientationVertical
+)
+
+// OrientationOf 由宽高判定画面方向
+func OrientationOf(width, height int) Orientation {
+	switch {
+	case width > height:
+		return OrientationHorizontal
+	case width < height:
+		return OrientationVertical
+	default:
+		return OrientationSquare
+	}
+}
+
+func (o Orientation) String() string {
+	switch o {
+	case OrientationHorizontal:
+		return "横屏"
+	case OrientationVertical:
+		return "竖屏"
+	default:
+		return "等比"
+	}
+}
+
+// ImageDir 返回图片归类子目录名，如 "图片_横屏_1080P" / "图片_GIF"
+func ImageDir(ext string, width, height int) string {
+	if strings.EqualFold(ext, ".gif") {
+		return "图片_GIF"
+	}
+	return resolutionDir("图片", ext, width, height)
+}
+
+// VideoDir 返回视频归类子目录名，如 "视频_竖屏_4k" / "视频_横屏_GIF"
+func VideoDir(ext string, width, height int) string {
+	return resolutionDir("视频", ext, width, height)
+}
+
+func resolutionDir(kind, ext string, width, height int) string {
+	ori := OrientationOf(width, height).String()
+	if strings.EqualFold(ext, ".gif") {
+		return kind + "_" + ori + "_GIF"
+	}
+	if suffix := matchStandard(width, height); suffix != "" {
+		return kind + "_" + ori + "_" + suffix
+	}
+	overflow := "原图"
+	if kind == "视频" {
+		overflow = "原画质"
+	}
+	return kind + "_" + ori + "_" + levelName(longEdge(width, height), overflow)
+}
+
+// longEdge 返回长边像素
+func longEdge(w, h int) int {
+	if w > h {
+		return w
+	}
+	return h
+}

internal/classify/standard.go

@@ -0,0 +1,52 @@
+package classify
+
+import "fmt"
+
+// standardResolution 标准分辨率规则：宽高精确匹配
+type standardResolution struct {
+	width  int
+	height int
+	suffix string
+}
+
+var standardResolutions = []standardResolution{
+	{1280, 720, "720P"},          // 720p 标准高清
+	{1600, 900, "1D5KP"},         // 介于 HD 与 FHD 之间
+	{1920, 1080, "1080P"},        // 1080p 全高清
+	{2048, 1080, "2DKP"},         // 影院 2K
+	{2560, 1440, "2D5KP"},        // 2.5K
+	{2560, 1080, "UltraWide2KP"}, // 带鱼屏
+	{3440, 1440, "UltraWide3KP"}, // 带鱼屏
+	{5120, 2160, "UltraWide4KP"}, // 带鱼屏
+	{3840, 2160, "4KP"},          // 主流 4K
+	{4096, 2160, "4KHP"},         // DCI 4K
+	{7680, 4320, "8KP"},          // 8K
+}
+
+// 非标分辨率分档参数
+const (
+	bucketStep = 1024 // 每 1024px 一档
+	maxLevel   = 19   // 1K ~ 19K 共 19 档（普通另算 1 档，合计 20 档）
+)
+
+// matchStandard 精确匹配标准分辨率，命中返回后缀，否则返回空串
+func matchStandard(width, height int) string {
+	for _, r := range standardResolutions {
+		if r.width == width && r.height == height {
+			return r.suffix
+		}
+	}
+	return ""
+}
+
+// levelName 按长边分档：普通(<1024) / 1K~19K(每1024一档) / overflow(≥20480)
+func levelName(longEdge int, overflow string) string {
+	if longEdge < bucketStep {
+		return "普通"
+	}
+	level := longEdge / bucketStep
+	if level > maxLevel {
+		return overflow
+	}
+	return fmt.Sprintf("%dK", level)
+}