refactor: 提取 core 库 + 新增 CLI 版本

- 创建 Cargo workspace（core / src-tauri / cli 三 crate）
- core: 纯 Rust 库，零 Tauri 依赖，包含所有业务逻辑
- src-tauri/commands: 改为薄包装，调用 core 函数
- cli: 基于 clap 的命令行工具，支持 JSON 输出
- CLI 命令: list, add, remove, conflicts, scan, profile, check-admin

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

core/src/scanner.rs

@@ -0,0 +1,114 @@
+use std::collections::HashMap;
+use std::fs;
+use std::path::Path;
+
+const EXECUTABLE_EXTENSIONS: &[&str] = &["exe", "bat", "cmd", "com", "ps1"];
+
+#[derive(serde::Serialize, Clone)]
+pub struct ConflictLocation {
+    pub dir: String,
+    pub priority: usize,
+}
+
+#[derive(serde::Serialize, Clone)]
+pub struct ConflictEntry {
+    pub name: String,
+    pub locations: Vec<ConflictLocation>,
+}
+
+#[derive(serde::Serialize)]
+pub struct ToolGroup {
+    pub dir: String,
+    pub exists: bool,
+    pub exes: Vec<String>,
+}
+
+/// 扫描 PATH 中的可执行文件冲突
+///
+/// 遍历每个 PATH 目录，查找 .exe/.bat/.cmd/.com/.ps1 文件，
+/// 标记出现在多个目录中的同名文件（后面的目录会被前面的「遮蔽」）
+
+pub fn scan_conflicts(paths: Vec<String>) -> Result<Vec<ConflictEntry>, String> {
+    // exe_name (小写) → [(priority, dir)]
+    let mut map: HashMap<String, Vec<(usize, String)>> = HashMap::new();
+
+    for (priority, dir) in paths.iter().enumerate() {
+        let p = Path::new(dir);
+        if !p.is_dir() {
+            continue;
+        }
+        let entries = fs::read_dir(p).map_err(|e| format!("无法读取目录 {}: {}", dir, e))?;
+        for entry in entries.flatten() {
+            let fname = entry.file_name();
+            let name = fname.to_string_lossy();
+            if let Some(ext) = Path::new(name.as_ref()).extension() {
+                let ext_lower = ext.to_ascii_lowercase();
+                if EXECUTABLE_EXTENSIONS.contains(&ext_lower.to_str().unwrap_or("")) {
+                    let key = name.to_lowercase();
+                    map.entry(key).or_default().push((priority, dir.clone()));
+                }
+            }
+        }
+    }
+
+    let mut results: Vec<ConflictEntry> = map
+        .into_iter()
+        .filter(|(_, locs)| locs.len() >= 2)
+        .map(|(name, locs)| ConflictEntry {
+            name,
+            locations: locs
+                .into_iter()
+                .map(|(priority, dir)| ConflictLocation { dir, priority })
+                .collect(),
+        })
+        .collect();
+
+    results.sort_by(|a, b| a.name.cmp(&b.name));
+    Ok(results)
+}
+
+/// 扫描 PATH 中各目录提供的可执行文件
+///
+/// query 非空时只返回文件名包含关键词的结果
+
+pub fn scan_tools(paths: Vec<String>, query: String) -> Result<Vec<ToolGroup>, String> {
+    let query_lower = query.to_lowercase();
+    let mut groups: Vec<ToolGroup> = Vec::new();
+
+    for dir in &paths {
+        let p = Path::new(dir);
+        if !p.is_dir() {
+            groups.push(ToolGroup {
+                dir: dir.clone(),
+                exists: false,
+                exes: vec![],
+            });
+            continue;
+        }
+
+        let entries = fs::read_dir(p).map_err(|e| format!("无法读取目录 {}: {}", dir, e))?;
+        let mut exes: Vec<String> = Vec::new();
+
+        for entry in entries.flatten() {
+            let fname = entry.file_name();
+            let name = fname.to_string_lossy();
+            if let Some(ext) = Path::new(name.as_ref()).extension() {
+                let ext_lower = ext.to_ascii_lowercase();
+                if EXECUTABLE_EXTENSIONS.contains(&ext_lower.to_str().unwrap_or("")) {
+                    if query_lower.is_empty() || name.to_lowercase().contains(&query_lower) {
+                        exes.push(name.to_string());
+                    }
+                }
+            }
+        }
+
+        exes.sort();
+        groups.push(ToolGroup {
+            dir: dir.clone(),
+            exists: true,
+            exes,
+        });
+    }
+
+    Ok(groups)
+}