chore(infra): simplify Docker builds and remove unused WEB_BUILD_PROFILE

- Adjusted Dockerfile’s build process for production-only artifacts.
- Removed unused `WEB_BUILD_PROFILE` from `dc-gui.yaml`.
- Optimized Gradle settings for better caching and performance.
- Updated `.dockerignore` to include source packages previously excluded by mistake.

frontend/core/auth/src/commonMain/kotlin/at/mocode/frontend/core/auth/data/AuthApiClient.kt

@@ -9,6 +9,7 @@ import io.ktor.http.*
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
+// Force re-compile trigger for a Docker build
 @Serializable
 data class LoginResponse(
   val success: Boolean,