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/core/build.gradle.kts

@@ -6,6 +6,7 @@ plugins {
     alias(libs.plugins.kotlin.multiplatform)
     alias(libs.plugins.android.library)
     alias(libs.plugins.sqldelight)
+    alias(libs.plugins.metro)
 }
 
 kotlin {