fix: missing ai context like timezone, selected measures and dimensions

[AdityaHegde]

• Add the correct time range truncated by selected timezone. (Dependant on fix: changing timezone doesnt update the data until range re-select #8801 to make sure time range updates)
• Add selected dimensions
• Add selected measures
• Ensure these settings are used by analyst agent in querying metrics view.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!