chore(folio): add Metro DI plugin (1.0.0-RC4) to versions catalog

Adds dev.zacsweers.metro plugin alias and applies it to :core
as a smoke test. Compiler-plugin only, no KSP required.

examples/folio/build.gradle.kts

@@ -7,4 +7,5 @@ plugins {
     alias(libs.plugins.kotlin.plugin.serialization) apply false
     alias(libs.plugins.compose.multiplatform) apply false
     alias(libs.plugins.sqldelight) apply false
+    alias(libs.plugins.metro) apply false
 }