Squashed commit of the following:

commit 0d624137c2557c6eeb87020749e4977b821c2b5c
Author: Adrien <adrien.cesaro@proton.me>
Date:   Thu Apr 9 11:55:22 2026 +0200

    backend native image setup

backend/Dockerfile.native

@@ -0,0 +1,26 @@
+# ---- Pull Maven from its official image (avoids microdnf under QEMU) ----
+FROM maven:3.9.9-eclipse-temurin-21 AS maven-dist
+
+# ---- Build stage: GraalVM 25 + Maven ----
+ARG TARGETPLATFORM=linux/arm64
+FROM --platform=$TARGETPLATFORM ghcr.io/graalvm/native-image-community:25 AS build
+
+# Copy Maven from the official Maven image — no package installation needed
+COPY --from=maven-dist /usr/share/maven /opt/maven
+ENV PATH="/opt/maven/bin:$PATH"
+
+WORKDIR /app
+
+# Cache dependency resolution separately from source compilation
+COPY pom.xml .
+RUN mvn -Pnative dependency:resolve dependency:resolve-plugins -q
+
+# Build native executable
+COPY src ./src
+RUN mvn -Pnative package -DskipTests
+
+# ---- Runtime stage: minimal ARM64 distroless ----
+FROM --platform=$TARGETPLATFORM gcr.io/distroless/base-nossl-debian12
+COPY --from=build /app/target/ai-teacher-backend /app/ai-teacher-backend
+EXPOSE 8080
+ENTRYPOINT ["/app/ai-teacher-backend"]