feat: lint native-breaking backtick test names

[rasros]

What changed

• Add a checkNativeSafeTestNames verification task to the com.eignex.lint convention plugin. It scans **/*Test/kotlin/**/*.kt and fails with a file:line on any fun \…`whose name contains(, ), or #`.
• Wire it into check.

Why

Kotlin/Native (and Android dex) reject characters in backtick identifiers that the JVM accepts, so a test name like foo (#389) compiles for jvm but fails the native compile with a cryptic error. This catches it early with an actionable message instead of deep in the build.

Testing

./gradlew compileKotlin passes. Consumers pick it up via check once they bump the plugin version.