Add OCI Access Governance MCP server

[anuj-git1412]

Description

Adds a new MCP server for OCI Access Governance (AG), enabling interaction with AG APIs through MCP-compatible clients.

The server integrates with OCI IAM (OIDC) for authentication and uses client credentials flow to securely call AG APIs.

No existing issues are fixed by this change.

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Type of change

• New feature (non-breaking change which adds functionality)

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How Has This Been Tested?

• Unit tests implemented for models and tools
• All tests pass locally using pytest
• MCP tools validated using a test client (examples/ag_mcp_test_client.py)

Test Configuration:

• Python version: 3.13
• OS: macOS

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Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code where necessary
• I have made corresponding changes to the documentation (README)
• My changes generate no new warnings
• I have added tests that prove my feature works
• New and existing unit tests pass locally

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• anujtripathi1412@gmail.com (@an12uj)

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