Schema explorer column name is squeezed to zero width by long type names

## What

In the schema explorer's column list, a long type name pushes the column name span to zero width. The name is still in the DOM, but nothing of it is visible.

## Where

src/components/schema-explorer/ColumnList.tsx:24-34

```tsx

The name span is `flex-1 truncate`, so it shrinks. The type span has no `shrink-0`, no `truncate` and no width cap, so it takes whatever it needs. `column.type.split("(")[0]` only trims a parenthesised length, so `timestamp without time zone` passes through whole.

Reproduce with any PostgreSQL table that has a `TIMESTAMP WITHOUT TIME ZONE` column. In a default width sidebar the type wraps to two lines and the column name disappears.

## Expected

The column name stays readable. If anything is cut, it is the type.

## How to fix

Constrain the type span rather than the name: add `shrink-0` with a `max-w-*` and `truncate`, or let the type truncate first. A `title` attribute carrying the full type would keep the information available on hover.

## How to check

Open a PostgreSQL connection, expand a table with a `TIMESTAMP WITHOUT TIME ZONE` column, and confirm the column name is visible at the default sidebar width.