perf(recent-projects): stream codex session discovery

src/features/recent-projects/main/adapters/output/sources/CodexSessionFileRecentProjectsSourceAdapter.ts

@@ -345,18 +345,30 @@ async function listRecentJsonlFiles(
     if (!hasBudget()) {
       return;
     }
-    let entries;
+    let directoryHandle;
     try {
-      entries = await fs.readdir(directory, { withFileTypes: true, encoding: 'utf8' });
+      directoryHandle = await fs.opendir(directory, { encoding: 'utf8' });
     } catch {
       return;
     }
 
     directoriesVisited += 1;
-    const filePaths: string[] = [];
+    const fileBatch: string[] = [];
     const childDirectories: string[] = [];
+    const flushFileBatch = async (): Promise<void> => {
+      if (!fileBatch.length) {
+        return;
+      }
+      const batch = fileBatch.splice(0, fileBatch.length);
+      await collectFileStats(batch);
+    };
+
+    try {
+      for await (const entry of directoryHandle) {
+        if (!hasBudget()) {
+          return;
+        }
 
-    for (const entry of entries) {
         const entryPath = path.join(directory, entry.name);
         if (entry.isDirectory()) {
           if (depth < maxDepth) {
@@ -366,11 +378,17 @@ async function listRecentJsonlFiles(
         }
 
         if (entry.isFile() && entry.name.endsWith('.jsonl')) {
-        filePaths.push(entryPath);
+          fileBatch.push(entryPath);
+          if (fileBatch.length >= CODEX_SESSION_FILE_DISCOVERY_STAT_BATCH_SIZE) {
+            await flushFileBatch();
           }
         }
+      }
+    } catch {
+      return;
+    }
 
-    await collectFileStats(filePaths);
+    await flushFileBatch();
 
     for (const childDirectory of childDirectories) {
       if (!hasBudget()) {

test/features/recent-projects/main/adapters/output/CodexSessionFileRecentProjectsSourceAdapter.test.ts

@@ -742,6 +742,7 @@ describe('CodexSessionFileRecentProjectsSourceAdapter', () => {
         )
       )
     );
+    const readdirSpy = vi.spyOn(fs, 'readdir');
 
     const adapter = new CodexSessionFileRecentProjectsSourceAdapter({
       getActiveContext: () => ({ type: 'local', id: 'local-1' }) as never,
@@ -767,6 +768,7 @@ describe('CodexSessionFileRecentProjectsSourceAdapter', () => {
         skippedUncached: 340,
       })
     );
+    expect(readdirSpy).not.toHaveBeenCalled();
   });
 
   it('skips non-interactive and ephemeral sessions', async () => {