feat(s3): base64 内嵌图片纳入未上传检测与上传（用户指正）

初版把 data: 一律排除在「未上传」外——未落盘文档粘贴的图、导入
文档自带的图都是 data:image/...;base64 形态，批量/右键/状态栏全
检测不到。现 isUploadableImageSrc = 本地文件引用 ∪ base64 内嵌图：
base64 图走新命令 s3_upload_base64（总数 31 对账），前端剥前缀传
纯 base64、Rust 解码后与文件图共用同一条 PUT 通路；对象名按内容
哈希（FNV-1a）生成，同图同名幂等。未落盘文档粘贴图也挂上自动上传。
进度/报错展示名对 base64 图用其哈希名，不再漏出 base64 串。
验证：独立 crate 对模拟 S3 实测 base64 解码 PUT；vitest 136+2、构建通过。

src-tauri/Cargo.lock

@@ -2029,6 +2029,7 @@ dependencies = [
 name = "new-markdown"
 version = "0.1.0"
 dependencies = [
+ "base64 0.22.1",
  "encoding_rs",
  "hmac",
  "reqwest 0.12.28",

src-tauri/Cargo.toml

@@ -22,3 +22,4 @@ trash = "5"
 reqwest = { version = "0.12", default-features = false, features = ["blocking", "rustls-tls"] }
 sha2 = "0.10"
 hmac = "0.12"
+base64 = "0.22"

src-tauri/src/commands.rs

@@ -941,6 +941,17 @@ pub async fn s3_upload_image(
         .map_err(|e| format!("上传任务失败：{e}"))?
 }
 
+#[tauri::command]
+pub async fn s3_upload_base64(
+    config: crate::s3::S3Config,
+    base64: String,
+    file_name: String,
+) -> Result<String, String> {
+    tauri::async_runtime::spawn_blocking(move || crate::s3::upload_base64(&config, &base64, &file_name))
+        .await
+        .map_err(|e| format!("上传任务失败：{e}"))?
+}
+
 #[tauri::command]
 pub async fn s3_test_connection(config: crate::s3::S3Config) -> Result<String, String> {
     tauri::async_runtime::spawn_blocking(move || crate::s3::test_connection(&config))

src-tauri/src/lib.rs

@@ -68,6 +68,7 @@ pub fn run() {
             commands::git_set_remote,
             commands::git_sync_now,
             commands::s3_upload_image,
+            commands::s3_upload_base64,
             commands::s3_test_connection,
             commands::delete_to_trash,
             commands::db_recent_list,

src-tauri/src/s3.rs

@@ -161,6 +161,25 @@ pub fn upload(cfg: &S3Config, file_path: &str, file_name: &str) -> Result<String
         return Err("图片超过 64MB，未上传。".into());
     }
     let bytes = std::fs::read(file_path).map_err(|e| format!("读取待上传图片失败：{e}"))?;
+    upload_bytes(cfg, &bytes, file_name)
+}
+
+/// 上传文档内嵌的 base64 图片（data:image/...;base64 数据，前端已剥掉前缀）。
+/// 未落盘文档粘贴的图片只有这种形态，没有文件可读。
+pub fn upload_base64(cfg: &S3Config, base64_str: &str, file_name: &str) -> Result<String, String> {
+    validate(cfg)?;
+    use base64::Engine;
+    let bytes = base64::engine::general_purpose::STANDARD
+        .decode(base64_str.trim())
+        .map_err(|e| format!("图片 base64 解码失败：{e}"))?;
+    if bytes.len() as u64 > MAX_IMAGE_BYTES {
+        return Err("图片超过 64MB，未上传。".into());
+    }
+    upload_bytes(cfg, &bytes, file_name)
+}
+
+fn upload_bytes(cfg: &S3Config, bytes: &[u8], file_name: &str) -> Result<String, String> {
+    let bytes = bytes.to_vec();
     let key = object_key(cfg, file_name);
     let (url, host, canonical_uri) = target(cfg, &key);
     let payload_hash = sha256_hex(&bytes);