fix: resolve attachment export inconsistencies (#108)

- Unify filename encoding between tryCopyImage and tryCopyMarkdownByRead
  (both now use encodeURI(fileName) when fileNameEncode is off)
- Add check to skip copying when source and target paths are identical
  (prevents file corruption for attachments already in output folder)

Fixes issues where:
- Some attachments had encoded names while others didn't
- Attachment files were corrupted during export
- Attachments were placed in different folders inconsistently

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: bingryan

src/utils.ts

@@ -355,7 +355,7 @@ export async function tryCopyImage(
                     const fileName = path.parse(path.basename(imageLink)).name;
                     const imageLinkMd5 = plugin.settings.fileNameEncode
                         ? md5(imageLink)
-                        : fileName;
+                        : encodeURI(fileName);
                     const imageExt = path.extname(imageLink);
                     const ifile = plugin.app.metadataCache.getFirstLinkpathDest(
                         imageLink,
@@ -394,6 +394,12 @@ export async function tryCopyImage(
                         )
                         .replace(/\\/g, "/");
 
+                    // Skip if source and target are the same (prevents file corruption)
+                    // This can happen when an attachment is already in the output folder
+                    if (filePath === targetPath) {
+                        continue;
+                    }
+
                     try {
                         if (!fileExists(targetPath)) {
                             if (