[Feature] Add Banxico Provider for USD/MXN Historical Data

[tania-rp]

Pull Request the OpenBB Platform

Description

• Summary of the change/bug fix.

Adds a Banco de México (Banxico) provider for historical USD/MXN FIX exchange-rate data using SIE series SF43718.

The provider:

• Integrates with currency.price.historical.

• Supports USDMXN and USD-MXN.

• Requires a Banxico SIE token configured as banxico_api_key.

• Skips observations reported as unavailable (N/E).

• Includes provider registration, documentation, tests, and a sanitized HTTP cassette.

• Link # issue, if applicable.

No linked issue.

• Screenshot of the feature or the bug before/after fix, if applicable.

Not applicable; this is a data-provider integration.

• Relevant motivation and context.

Banxico is the authoritative source for Mexico's official FIX exchange rate. This provider makes historical USD/MXN FIX observations available through OpenBB's standard currency historical-data interface.

• List any dependencies that are required for this change.

Requires openbb-core ^1.6.10 and a free Banxico SIE API token for live requests. No additional runtime dependencies were introduced.

How has this been tested?

The provider test suite was executed with:

cd openbb_platform/providers/banxico
python -m pytest tests/test_banxico_fetchers.py -q

Result: 6 passed.

Additional validations completed successfully:

ruff check openbb_platform/providers/banxico openbb_platform/dev_install.py
ruff format --check openbb_platform/providers/banxico
poetry check --lock
poetry build
git diff --check

The complete fetcher flow is covered by a sanitized HTTP cassette containing MOCK_TOKEN and MOCK_COOKIE.

• Ensure all unit and integration tests pass.
• If you modified/added command(s):
  • Ensure the command(s) execute with the expected output.
    • API.
    • Python Interface.
  • If applicable, add new tests for the command.
• If a new provider was introduced or a new fetcher was added:
  • Ensure the existing provider tests pass.
  • Ensure the new provider and/or fetcher is stable and usable.
  • Add new tests for the provider and/or fetcher.
• If a new provider or extension was added:
  • Update the list of Extensions.
  • Update the list of Providers.
  • Update the community integration-test workflow.

The referenced openbb_platform/EXTENSIONS.md, openbb_platform/PROVIDERS.md, and .github/workflows/platform-api-integration-test.yml files are not present in the current develop branch, so these items are not applicable.

Checklist

• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have adhered to the GitFlow branch naming convention.
• I am following the OpenBB Platform contributing guidelines.
  • I have added tests for the new provider and fetcher.

[CLAassistant]

All committers have signed the CLA.