The online search giant's AI-driven momentum is impressive. But today's price leaves little room for missteps.After a difficult stretch in which some investors worried it was falling behind in AI (artificial intelligence), Alphabet (GOOGL +0.26%) (GOOG +0.29%) has become one of 2025's standout winners. The parent of Google Search, YouTube, and a fast-growing cloud platform has seen its stock climb about 66% year to date as enthusiasm builds around its Gemini AI models and custom data center chips.The rally ...