feat: finish rust web dual pane document shell

rust/crates/mnote-web/src/routes/local_folder_source.rs

@@ -2655,6 +2655,15 @@ fn local_markdown_conflict_detection_key(
     document_id: &str,
     markdown_path: &Path,
 ) -> Result<String, WebError> {
+    let content = fs::read(markdown_path).map_err(|error| {
+        WebError::bad_request_code(
+            "local_markdown_read_failed",
+            format!(
+                "无法读取本地 Markdown 文件 {}: {error}",
+                markdown_path.display()
+            ),
+        )
+    })?;
     let meta = fs::metadata(markdown_path).map_err(|error| {
         WebError::bad_request_code(
             "local_markdown_stat_failed",
@@ -2665,8 +2674,11 @@ fn local_markdown_conflict_detection_key(
         )
     })?;
     let modified_ms = system_time_ms(meta.modified().unwrap_or(SystemTime::UNIX_EPOCH));
+    let mut hasher = DefaultHasher::new();
+    content.hash(&mut hasher);
+    let content_hash = hasher.finish();
     Ok(format!(
-        "local-md:{document_id}:{modified_ms}:{}",
+        "local-md:{document_id}:{modified_ms}:{}:{content_hash:016x}",
         meta.len()
     ))
 }
@@ -2965,6 +2977,25 @@ mod tests {
         let _ = std::fs::remove_dir_all(&root);
     }
 
+    #[test]
+    fn local_markdown_conflict_detection_key_changes_when_content_changes_with_same_size() {
+        let root = temp_root("mnote-local-conflict-key-content");
+        let file = root.join("README.md");
+        std::fs::write(&file, "aaaa\n").expect("write first content");
+
+        let first = super::local_markdown_conflict_detection_key("local-md:README.md", &file)
+            .expect("first conflict key");
+
+        std::fs::write(&file, "bbbb\n").expect("write second content");
+
+        let second = super::local_markdown_conflict_detection_key("local-md:README.md", &file)
+            .expect("second conflict key");
+
+        assert_ne!(first, second);
+
+        let _ = std::fs::remove_dir_all(&root);
+    }
+
     #[test]
     fn local_markdown_parser_covers_basic_blocks_and_attachment_refs() {
         let blocks = crate::routes::local_markdown_parser::markdown_to_blocks(