refactor: 合并为单 crate，前端改为内嵌 React 控制台

合并 stash-cli / stash-core 为根目录单 crate（lib + bin），新增 React + Vite + TS 控制台替换 Askama 模板。
build.rs 用 walkdir 把 stash-web/dist 同步到 $OUT_DIR/web，由 include_dir! 编译期内嵌，产出单文件二进制。
路由改为 / 与 /assets/** 走内嵌前端，其余交给 ServeDir，缺失路径返回内置 404。同步更新依赖、.gitignore 与 README。

src/listing.rs

@@ -0,0 +1,160 @@
+use serde::Serialize;
+use std::{fmt::Write as _, path::Path};
+
+#[derive(Debug, Serialize, Clone, PartialEq, Eq)]
+pub struct AppProject {
+    pub name: String,
+    pub route_path: String,
+}
+
+impl AppProject {
+    pub fn initial(&self) -> String {
+        self.name
+            .chars()
+            .next()
+            .unwrap_or('A')
+            .to_uppercase()
+            .to_string()
+    }
+}
+
+pub fn scan_projects(root: &Path) -> Vec<AppProject> {
+    let mut projects = Vec::new();
+
+    let Ok(read_dir) = std::fs::read_dir(root) else {
+        return projects;
+    };
+
+    for item in read_dir.flatten() {
+        let path = item.path();
+        let name = item.file_name().to_string_lossy().to_string();
+
+        if name.starts_with('.') {
+            continue;
+        }
+
+        if path.is_dir() {
+            let has_index = path.join("index.html").exists() || path.join("index.htm").exists();
+            if has_index {
+                let route_path = format!("/{}/", encode_path_segment(&name));
+                projects.push(AppProject { name, route_path });
+            }
+        }
+    }
+
+    projects.sort_by(|a, b| {
+        a.name
+            .to_lowercase()
+            .cmp(&b.name.to_lowercase())
+            .then_with(|| a.name.cmp(&b.name))
+    });
+    projects
+}
+
+fn encode_path_segment(segment: &str) -> String {
+    let mut encoded = String::with_capacity(segment.len());
+
+    for byte in segment.bytes() {
+        if byte.is_ascii_alphanumeric() || matches!(byte, b'-' | b'_' | b'.' | b'~') {
+            encoded.push(char::from(byte));
+        } else {
+            write!(&mut encoded, "%{byte:02X}").expect("写入字符串不会失败");
+        }
+    }
+
+    encoded
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::{
+        fs,
+        path::PathBuf,
+        sync::atomic::{AtomicU64, Ordering},
+    };
+
+    static NEXT_TEMP_ID: AtomicU64 = AtomicU64::new(0);
+
+    struct TestDir {
+        path: PathBuf,
+    }
+
+    impl TestDir {
+        fn new() -> Self {
+            let id = NEXT_TEMP_ID.fetch_add(1, Ordering::Relaxed);
+            let path =
+                std::env::temp_dir().join(format!("stash-core-test-{}-{id}", std::process::id()));
+            fs::create_dir_all(&path).expect("应能创建测试目录");
+            Self { path }
+        }
+
+        fn path(&self) -> &Path {
+            &self.path
+        }
+
+        fn add_project(&self, name: &str, index_file: &str) {
+            let project = self.path.join(name);
+            fs::create_dir_all(&project).expect("应能创建项目目录");
+            fs::write(project.join(index_file), "<!doctype html>").expect("应能创建入口文件");
+        }
+    }
+
+    impl Drop for TestDir {
+        fn drop(&mut self) {
+            let _ = fs::remove_dir_all(&self.path);
+        }
+    }
+
+    #[test]
+    fn scan_projects_detects_only_immediate_visible_projects() {
+        let root = TestDir::new();
+        root.add_project("with-html", "index.html");
+        root.add_project("with-htm", "index.htm");
+        root.add_project(".hidden", "index.html");
+        root.add_project("no-index", "readme.txt");
+        root.add_project("parent/child", "index.html");
+        fs::create_dir_all(root.path().join("plain-directory")).expect("应能创建普通目录");
+
+        let names: Vec<_> = scan_projects(root.path())
+            .into_iter()
+            .map(|project| project.name)
+            .collect();
+
+        assert_eq!(names, vec!["with-htm", "with-html"]);
+    }
+
+    #[test]
+    fn scan_projects_sorts_names_case_insensitively() {
+        let root = TestDir::new();
+        root.add_project("zeta", "index.html");
+        root.add_project("ALPHA", "index.html");
+        root.add_project("middle", "index.html");
+
+        let names: Vec<_> = scan_projects(root.path())
+            .into_iter()
+            .map(|project| project.name)
+            .collect();
+
+        assert_eq!(names, vec!["ALPHA", "middle", "zeta"]);
+    }
+
+    #[test]
+    fn scan_projects_url_encodes_route_segments() {
+        let root = TestDir::new();
+        root.add_project("space name", "index.html");
+        root.add_project("中文", "index.html");
+
+        let projects = scan_projects(root.path());
+
+        assert_eq!(projects[0].name, "space name");
+        assert_eq!(projects[0].route_path, "/space%20name/");
+        assert_eq!(projects[1].name, "中文");
+        assert_eq!(projects[1].route_path, "/%E4%B8%AD%E6%96%87/");
+    }
+
+    #[test]
+    fn path_segment_encoding_preserves_unreserved_characters() {
+        assert_eq!(encode_path_segment("aZ09-_.~/?#%"), "aZ09-_.~%2F%3F%23%25");
+    }
+}