SONARIAC-2741 Isolate tree-sitter native library extraction per module (#105)

## Summary
- Set `tree-sitter-lib` system property per test JVM to isolate native
library extraction directories
- Each module extracts tree-sitter native libraries to its own
`build/tree-sitter-native/` directory
- Fixes intermittent `LinkageError` on Windows CI caused by parallel
Gradle test JVMs racing to extract the same `.dll` to a shared
`~/.tree-sitter/` path

## Context
The "QA Windows OS Tests" CI job in sonar-iac-enterprise fails
intermittently because Windows locks DLL files while loaded, preventing
concurrent extraction by parallel test JVMs. Linux is unaffected because
`.so` files are not locked on disk.

tree-sitter-ng's `NativeUtils.getLibStorePath()` checks
`System.getProperty("tree-sitter-lib")` first, falling back to
`${user.home}/.tree-sitter`. By setting this property per module, each
test JVM gets its own extraction path.

## Test plan
- [x] shell and docker tests pass locally when run in parallel
- [x] Verified separate extraction:
`shell/build/tree-sitter-native/lib/` and
`docker/build/tree-sitter-native/lib/` each contain their own `.dll`
copies
- [ ] Windows CI no longer fails intermittently

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: rudy-regazzoni-sonarsource

gradle-modules/src/main/kotlin/org.sonarsource.cloud-native.java-conventions.gradle.kts

@@ -45,6 +45,11 @@ tasks.withType<Javadoc> {
 tasks.withType<Test> {
     useJUnitPlatform()
 
+    // Each module gets its own tree-sitter native library extraction directory.
+    // Without this, parallel Gradle test JVMs race to extract the same .dll to ${user.home}/.tree-sitter/,
+    // which causes LinkageError on Windows due to file locking (SONARIAC-2741).
+    systemProperty("tree-sitter-lib", layout.buildDirectory.dir("tree-sitter-native").get().asFile.absolutePath)
+
     testLogging {
         // log the full stack trace (default is the 1st line of the stack trace)
         exceptionFormat = TestExceptionFormat.FULL