[Task]: Add support to exclude non‑schema .sql scripts from build

### Feature Description

Provide an option to automatically exclude files from the build during creation.

### Problem and Motivation

Today, standalone T‑SQL statement .sql files are treated as part of the build unless they are correctly referenced through pre‑ or post‑deployment scripts. This causes:

- Unexpected build errors when a script is accidentally included
- Confusion for users adding ad‑hoc, debugging, or operational scripts
- Extra manual steps to mark or reference files correctly

### Related Area

- [ ] Connection dialog (SQL Server | Azure browse/Fabric browse)
- [ ] Query editor
- [ ] Query results panel
- [ ] Object Explorer
- [ ] GitHub Copilot integration
- [ ] Preview/Edit data
- [ ] Table Designer
- [ ] Schema Designer
- [ ] Schema Compare
- [ ] Local SQL Server Container provisioning
- [ ] SQL database in Fabric provisioning
- [ ] DACPAC/BACPAC export/import
- [x] SQL Database projects
- [ ] Query Plan Visualizer
- [ ] Other (please describe below)

### If you selected "Other", please describe the area

_No response_

### Confirmation

- [x] I have searched existing feature requests and couldn't find a match
- [x] I want to help implement this feature