Add OAuth authentication method for Snowflake

[catstrike]

Add SnowflakeOAuthAuth

[Copilot]

Pull request overview

Adds a new Snowflake authentication config model intended to support OAuth-based connections, and exposes it via the package public API.

Changes:

• Introduces SnowflakeOAuthAuth with a secret token field.
• Extends SnowflakeConnectionProperties.auth union to accept SnowflakeOAuthAuth.
• Exports SnowflakeOAuthAuth from databao_context_engine.__init__.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/databao_context_engine/plugins/databases/snowflake/config_file.py	Adds OAuth auth model and makes it selectable in Snowflake connection config.
src/databao_context_engine/__init__.py	Re-exports the new auth model for external consumers.

Comments suppressed due to low confidence (1)

src/databao_context_engine/plugins/databases/snowflake/config_file.py:47

• SnowflakeOAuthAuth currently only contributes token into to_snowflake_kwargs(). Snowflake’s Python connector requires authenticator='oauth' (in addition to token) for OAuth-based connections; without setting this, snowflake.connector.connect(**kwargs) will still use the default authenticator and the token will be ignored / auth will fail. Consider either adding an authenticator field to SnowflakeOAuthAuth with a default of 'oauth', or special-casing to_snowflake_kwargs() to inject authenticator='oauth' when self.auth is a SnowflakeOAuthAuth.

    def to_snowflake_kwargs(self) -> dict[str, Any]:
        kwargs = self.model_dump(
            exclude={
                "additional_properties": True,
            },
            exclude_none=True,
        )
        auth_fields = kwargs.pop("auth", {})
        kwargs.update(auth_fields)
        kwargs.update(self.additional_properties)

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[JulienArzul]

You've checked that it works right?

From what I remember, we flatten the attributes within the auth objects, meaning that the token argument will be passed directly to the Snowflake connect method

[SimonKaran13]

@JulienArzul yes, it's tested.