Insert Row modal: primary action button labelled 'Review SQL' should say 'Insert'

## Problem
The primary action button in the "Insert row" modal is labelled **"Review SQL"** rather than something that conveys the insertion intent.

This creates two issues:
1. The modal title says "Insert row" but the button says "Review SQL" — the action described by the button does not match the stated goal
2. "Review SQL" implies the flow will show a SQL preview step before executing — but the intent is simply to insert a row

## Expected behaviour
- The button should be labelled **"Insert"**, **"Insert row"**, or **"Save"**
- If a SQL preview step is genuinely intended as a safety measure, it should be a secondary option (e.g., a small "Preview SQL" link), not the primary CTA

## Current state
Modal title: "Insert row" | Primary button: "Review SQL"