.NET AI freshness pass

[alexwolfmsft]

Summary

Describe your changes here.

Fixes #Issue_Number (if available)

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📄 File	🔗 Preview link
docs/ai/conceptual/agents.md	How agents and copilots work with LLMs
docs/ai/conceptual/chain-of-thought-prompting.md	"Chain of Thought Prompting - .NET"
docs/ai/conceptual/how-genai-and-llms-work.md	How generative AI and LLMs work
docs/ai/conceptual/rag.md	Retrieval-augmented generation (RAG) provides LLM knowledge
docs/ai/conceptual/vector-databases.md	docs/ai/conceptual/vector-databases
docs/ai/conceptual/zero-shot-learning.md	Zero-shot and few-shot learning
docs/ai/dotnet-ai-ecosystem.md	Overview of the .NET + AI ecosystem
docs/ai/how-to/app-service-aoai-auth.md	Authenticate an AI app hosted on Azure App Service to Azure OpenAI using Microsoft Entra ID
docs/ai/how-to/app-service-db-auth.md	[System-assigned](https://review.learn.microsoft.com/en-us/dotnet/ai/how-to/app-service-db-auth?branch=pr-en-us-43767)
docs/ai/how-to/use-redis-for-memory.md	docs/ai/how-to/use-redis-for-memory
docs/ai/quickstarts/quickstart-local-ai.md	Chat with a local AI model using .NET and Semantic Kernel
docs/ai/tutorials/llm-eval.md	Tutorial: Evaluate an LLM's prompt completions
docs/ai/tutorials/tutorial-ai-vector-search.md	Tutorial - Integrate OpenAI with the RAG pattern and vector search using Azure Cosmos DB for MongoDB

[gewarren]

One suggestion to match the tense of the other bullet.