Insert Row modal: tinyint(1) boolean fields should be a checkbox or toggle, not a text input

## Problem
In the "Insert row" modal, `tinyint(1)` columns (which represent boolean values) are rendered as plain text inputs instead of checkboxes or toggles.

## Current state
- `is_verified tinyint(1)` — plain text input with placeholder "default: 0"
- `is_premium tinyint(1)` — plain text input with placeholder "NULL"

Users must type `0` or `1` manually, which is error-prone and confusing.

## Expected behaviour
`tinyint(1)` columns should render as a checkbox or toggle switch. This:
- Clearly communicates the boolean nature of the field
- Prevents invalid values
- Is consistent with how these values are displayed in the results grid (as `true`/`false`)

## Note
The results grid already displays `tinyint(1)` values as `true`/`false` — the insert form should be consistent with that representation.