chore: remove all kimi oauth authentication integration

[compgeniuses]

Description

This commit fully strips out the Kimi OAuth authentication integration from the codebase:

• delete all Kimi-related utility files, type definitions, and API handlers
• remove @contracts path aliases from all TypeScript configuration files
• uninstall the kimi-plugin-inspect-react development dependency
• strip all Kimi-specific environment variables from CI, docker, and local configs
• simplify the auth context to remove Kimi OAuth fallback authentication
• remove the OAuth callback route from the main server bootstrapper

Fixes #(issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactor (no functional changes)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

• Unit tests
• Integration tests
• End-to-end tests
• Manual testing

Test Configuration:

• Node.js version:
• PostgreSQL version:
• OS:

Checklist:

• My code follows the project's code style
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshots (if appropriate):

Additional context:

Add any other context about the pull request here.