feat: Support custom scopes and maxQueryResultRows

[shobsi]

After this change the user can optionally control authorization scopes for BigQuery interaction and max rows for query results via environment variables, e.g.:

$ export BIGQUERY_SCOPES="https://www.googleapis.com/auth/bigquery,https://www.googleapis.com/auth/drive"

$ export BIGQUERY_MAX_QUERY_RESULT_ROWS=50

This change addresses #76

[averikitsch]

Can you add these settings to the README?
We can also add them to settings in https://github.com/gemini-cli-extensions/bigquery-conversational-analytics/blob/main/gemini-extension.json so the CLI prompts the users to configure these as well.

[shobsi]

Can you add these settings to the README? We can also add them to settings in https://github.com/gemini-cli-extensions/bigquery-conversational-analytics/blob/main/gemini-extension.json so the CLI prompts the users to configure these as well.

Done, thanks!

[shobsi]

Can you add these settings to the README? We can also add them to settings in https://github.com/gemini-cli-extensions/bigquery-conversational-analytics/blob/main/gemini-extension.json so the CLI prompts the users to configure these as well.

Done, thanks!

I meant done in README. Since these are optional, we don't need to add them in gemini-extension.json? @averikitsch

[shobsi]

Can you add these settings to the README? We can also add them to settings in https://github.com/gemini-cli-extensions/bigquery-conversational-analytics/blob/main/gemini-extension.json so the CLI prompts the users to configure these as well.

Done, thanks!

I meant done in README. Since these are optional, we don't need to add them in gemini-extension.json? @averikitsch

Never mind, I see optional can go there too, so added. PTAL, thanks!