fix: serialize git status/stage/commit/log results for IPC transfer

simple-git returns objects with Map/Set fields that cannot be cloned
over Electron IPC. Flatten all git operation results into plain
JSON-serializable objects to fix 'An object could not be cloned' error.

src/main/GitOperations.js

@@ -7,9 +7,20 @@ function getGitInstance(dir) {
 async function getStatus(dir) {
   try {
     const git = getGitInstance(dir);
-    return await git.status();
+    const result = await git.status();
+    const files = [];
+    for (const [filePath, status] of Object.entries(result.files || {})) {
+      files.push({
+        filePath,
+        status: status.working_dir === 'M' ? 'modified'
+          : status.working_dir === 'A' || status.index === 'A' ? 'added'
+          : status.working_dir === 'D' || status.index === 'D' ? 'deleted'
+          : 'untracked',
+      });
+    }
+    return { files };
   } catch (_err) {
-    return { error: 'Not a git repository' };
+    return { files: [], error: 'Not a git repository' };
   }
 }
 
@@ -17,16 +28,25 @@ async function stage(dir, files) {
   try {
     const git = getGitInstance(dir);
     await git.add(files);
-    return await git.status();
+    const result = await git.status();
+    const staged = [];
+    for (const [filePath, status] of Object.entries(result.files || {})) {
+      staged.push({
+        filePath,
+        status: status.index === 'A' ? 'added' : status.index === 'M' ? 'modified' : status.index === 'D' ? 'deleted' : 'untracked',
+      });
+    }
+    return { files: staged };
   } catch (err) {
-    return { error: err.message };
+    return { files: [], error: err.message };
   }
 }
 
 async function commit(dir, message) {
   try {
     const git = getGitInstance(dir);
-    return await git.commit(message);
+    const result = await git.commit(message);
+    return { summary: result?.summary || 'Committed' };
   } catch (err) {
     return { error: err.message };
   }
@@ -35,9 +55,18 @@ async function commit(dir, message) {
 async function log(dir, maxCount = 20) {
   try {
     const git = getGitInstance(dir);
-    return await git.log({ maxCount });
+    const result = await git.log({ maxCount });
+    return {
+      latest: result?.latest || null,
+      all: (result?.all || []).map((entry) => ({
+        hash: entry.hash,
+        message: entry.message,
+        author: entry.author_name,
+        date: entry.date,
+      })),
+    };
   } catch (err) {
-    return { error: err.message };
+    return { all: [], error: err.message };
   }
 }