[FEAT] Support star-expansion of columns in vscode

This request partly relates to https://github.com/dbt-labs/dbt-fusion/issues/650 but is slightly different.

**Is your feature request related to a particular component of the dbt Fusion Engine**
- [ ] CLI Features
- [ ] Adapter or Database Driver Features
- [ ] SQL Understanding Features
- [x] VS Code extension

**Describe the solution you'd like**

A competing IDE includes this feature for SQL and dbt:

* place the cursor onto a star character within a SELECT statement,
* press the right hotkey (or use corresponding nav menu)
* the IDE expands the star into all of its underpinning columns

See below demo.

This is an ***incredibly useful feature***, because it saves us having to write out every single column, every single model.

(Instead, developers can use the star expansion, and then just peel it back to the columns they care about).

https://github.com/user-attachments/assets/c894d2bf-eed3-46f9-87f4-ee6098ffdd9f

```sql
WITH foo AS (
SELECT
column1 AS colour,
column1 AS foo,
column1 AS bar
FROM (VALUES ('a'))
)

SELECT
colour,
foo,
bar
FROM foo
```