Release 0.9.2: publish codegen to Maven Central

[AndroidPoet]

Publishes the supabase-codegen CLI/library and the io.github.androidpoet.supabase.codegen Gradle plugin to Maven Central via the existing publishing pipeline, and bumps all modules to a unified 0.9.2.

What

• Wire both codegen modules into Maven Central publishing (incl. the Gradle plugin marker).
• Bump version 0.9.1 → 0.9.2 (pre-stable patch, unified across all modules).
• CHANGELOG 0.9.2 section.

Usage after release

// settings.gradle.kts → pluginManagement { repositories { mavenCentral() } }
plugins { id("io.github.androidpoet.supabase.codegen") version "0.9.2" }

The generator is a JVM build-time tool (like supabase gen types); only its output is multiplatform-common, so it works for any KMP target set including Android+iOS-only.

Artifacts already published and released to Maven Central; tag 0.9.2 pushed.