docs: add missing README files for four example directories

[mitre88]

Summary

This PR adds README documentation to four example directories that were previously missing them:

• examples/podcast/ — Documents the podcast transcript processing example, including transcript parsing, multi-speaker episode ingestion, and temporal ordering.
• examples/wizard_of_oz/ — Documents the literary text processing example using The Wizard of Oz, including the Anthropic LLM client usage and chapter-based episode splitting.
• examples/ecommerce/ — Documents the e-commerce sales conversation example, covering product knowledge extraction and customer preference tracking.
• examples/langgraph-agent/ — Documents the LangGraph integration example for building an interactive ShoeBot sales agent with Graphiti-powered memory.

Motivation

The examples/quickstart/, examples/azure-openai/, examples/opentelemetry/, and examples/gliner2/ directories all have README files, but the other four examples did not. This makes it harder for new users to discover and understand these examples.

Each README follows the same structure as the existing example READMEs:

• Overview of what the example does
• Prerequisites and setup instructions
• How to run the example
• Key concepts demonstrated
• Cross-references to related examples

Changes

• Added examples/podcast/README.md
• Added examples/wizard_of_oz/README.md
• Added examples/ecommerce/README.md
• Added examples/langgraph-agent/README.md

No code changes.

[danielchalef]

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Install Anthropic extra before running Wizard of Oz example

The setup command omits the anthropic dependency even though runner.py imports AnthropicClient, whose module raises ImportError unless anthropic is installed (graphiti-core[anthropic] or anthropic directly). Following this README in a fresh environment will fail before the example can run.

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[chatgpt-codex-connector]

Document a runnable command for the Wizard of Oz runner

The documented command python runner.py does not work from examples/wizard_of_oz because runner.py uses from examples.wizard_of_oz.parser import ...; when run as a script from that directory, examples is not on sys.path and execution fails with ModuleNotFoundError. This needs a module-style invocation or adjusted import guidance so users can actually execute the example.

Useful? React with 👍 / 👎.