Fix OAuth2 PKCE Implementation Issues

[tcaldwell-x]

Problem

OAuth2 PKCE flows were broken due to:

• Python SDK: Incorrect authorization URL, wrong token endpoint path, outdated base URLs, and documentation errors
• TypeScript SDK: PKCE parameters not being included in authorization URL

Solution

• Python SDK: Hardcode authorization URL to https://x.com/i/oauth2/authorize, fix token endpoint to /2/oauth2/token, update default base_url to https://api.x.com, and correct all documentation examples
• TypeScript SDK: Include PKCE parameters (code_challenge, code_challenge_method) in authorization URL when set

Changes

• python/oauth2_auth.j2: Fix authorization URL, token endpoint path, and default base_url
• python/main_client.j2: Update default base_url
• python/process_for_mintlify.j2: Fix documentation examples (imports, parameters, method usage)
• typescript/oauth2_auth.j2: Add PKCE parameters to authorization URL

Impact

• OAuth2 PKCE flows now work correctly in both SDKs
• Documentation examples are accurate and functional
• No breaking changes - these are bug fixes that correct incorrect behavior

Testing

• Verify OAuth2 PKCE authorization flow completes successfully
• Confirm token exchange uses correct endpoints
• Validate documentation examples run without errors