🧪 Test: Prerelease label with insignificant change (#20)

## Summary

This PR tests the prerelease label scenario with an **insignificant**
file change.

## What changed

- Added `.idea/` to `.gitignore` (not an important file)

## Expected behavior

**Without prerelease label**: `HasImportantChanges` should be `false`
and build/test stages should be skipped.

**With prerelease label**: Even though no important files changed, the
`shouldPrerelease` flag should cause `$shouldRunBuildTest` to be `true`,
so build/test stages **should run**.

## Important files patterns (none match `.gitignore`)
- `^\.github/workflows/Process-PSModule\.yml$` ❌
- `^src/` ❌
- `^examples/` ❌
- `^README\.md$` ❌

## Verification

1. First run (without label): Build/test should be skipped
2. After adding `prerelease` label: Build/test should run

Author: MariusStorhaug

.gitignore

@@ -6,6 +6,11 @@
 !.vscode/extensions.json
 *.code-workspace
 
+# IDE files
+.idea/
+.vscode/
+*.log
+
 # Local History for Visual Studio Code
 .history/*