[khvn26]

Runs the Flagsmith SDK behavioural spec against this SDK on every pull request and push to main.

# When the application gets the environment flags
def get_environment_flags(flagsmith: Flagsmith) -> list[SpecFlag]:
    return as_spec_flags(flagsmith.get_environment_flags())

• sdk-spec/steps.py: one function per SDK step, marked with the Gherkin step text as a comment. It contains only SDK calls and the mapping to the spec's flag shape, so it doubles as a working usage example. It is typed, so mypy --strict . covers it.
• sdk-spec/Dockerfile: builds the SDK from source and runs the steps file under the spec's Python harness, taken from the harness build context. The harness speaks JSON lines over stdin/stdout, so this repo contains no protocol code.
• .github/workflows/sdk-spec.yml: calls the spec's reusable workflow with language: python. The workflow starts a real Flagsmith instance, seeds it through the Admin API and runs the scenarios against the SDK image. It is pinned to v0.3.0.
• renovate.json: bumps the uses: ref and spec-ref together.

The spec currently covers getting environment flags and getting identity flags with traits.