feat: add framework-agnostic weaviate tool

[devin-ai-integration]

Implements a framework-agnostic Weaviate tool following the patterns established in PR #76.

Core Features:

• Vector search functionality via near-text queries
• Collection management (create/search)
• OpenAI integration for embeddings

Environment Variables:

• WEAVIATE_TOOL_URL: Weaviate cluster URL
• WEAVIATE_TOOL_API_KEY: Weaviate API key
• WEAVIATE_TOOL_OPENAI_API_KEY: OpenAI API key for embeddings

Dependencies:

• weaviate-client>=3.0.0
• openai>=1.0.0

Link to Devin run: https://app.devin.ai/sessions/6518007355e3462a88da18a124a2d15b

[devin-ai-integration]

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[tcdent]

Just one minor note about the naming of the environment variables:

WEAVIATE_TOOL_URL should be WEAVIATE_URL
WEAVIATE_TOOL_API_KEY should be WEAVIATE_API_KEY
WEAVIATE_TOOL_OPENAI_API_KEY should be WEAVIATE_OPENAI_API_KEY and default to the value of OPENAI_API_KEY

[bboynton97]

waiting on #76 to merge