fix: skip openai-dependent tests in CI with importorskip

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Joey Ashley

test/test_batch_integration.py

@@ -1,6 +1,7 @@
 """Integration tests for batch embedding functionality."""
 
 import pytest
+pytest.importorskip("openai")
 import tempfile
 import os
 import sqlite3

test/test_embedding_benchmarks.py

@@ -1,6 +1,7 @@
 """Performance benchmarks for batch embedding."""
 
 import pytest
+pytest.importorskip("openai")
 import time
 from unittest.mock import MagicMock
 from core.embedding_service import EmbeddingService