fix: all dockerfile build issues

Dockerfile

@@ -1,55 +1,26 @@
-FROM --platform=$BUILDPLATFORM rust:latest AS builder-base
-RUN apt-get update && \
-    apt-get install -y ffmpeg pkg-config libssl-dev && \
-    apt-get clean && \
-    rm -rf /var/lib/apt/lists/*
-WORKDIR /app
-COPY . .
-
-FROM builder-base AS builder-amd64
-ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=gcc
-RUN rustup target add x86_64-unknown-linux-gnu && \
-    cargo build --release --target x86_64-unknown-linux-gnu && \
-    mv target/x86_64-unknown-linux-gnu/release/backend /app/backend && \
-    rm -rf target src Cargo.toml Cargo.lock .git* && \
-    find . -type f ! -name 'backend' -delete
-
-FROM builder-base AS builder-arm64
-ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER=aarch64-linux-gnu-gcc
-RUN dpkg --add-architecture arm64 && \
-    apt-get update && \
-    apt-get install -y \
-        gcc-aarch64-linux-gnu \
-        libssl-dev:arm64 \
-        pkg-config \
-        crossbuild-essential-arm64 && \
-    rustup target add aarch64-unknown-linux-gnu && \
-    PKG_CONFIG_ALLOW_CROSS=1 \
-    PKG_CONFIG_PATH=/usr/lib/aarch64-linux-gnu/pkgconfig \
-    PKG_CONFIG_SYSROOT_DIR=/ \
-    OPENSSL_DIR=/usr/lib/aarch64-linux-gnu \
-    OPENSSL_LIB_DIR=/usr/lib/aarch64-linux-gnu \
-    OPENSSL_INCLUDE_DIR=/usr/include/aarch64-linux-gnu \
-    AARCH64_UNKNOWN_LINUX_GNU_OPENSSL_LIB_DIR=/usr/lib/aarch64-linux-gnu \
-    AARCH64_UNKNOWN_LINUX_GNU_OPENSSL_INCLUDE_DIR=/usr/include/aarch64-linux-gnu \
-    cargo build --release --target aarch64-unknown-linux-gnu && \
-    mv target/aarch64-unknown-linux-gnu/release/backend /app/backend && \
-    rm -rf target src Cargo.toml Cargo.lock .git* && \
-    find . -type f ! -name 'backend' -delete
-
-FROM ubuntu:22.04 AS runtime
+FROM rust:1.82.0 AS builder
+
+RUN USER=root cargo new --bin backend
+WORKDIR /backend
+
+COPY ./Cargo.lock ./Cargo.lock
+COPY ./Cargo.toml ./Cargo.toml
+
+RUN cargo build --release
+RUN rm src/*.rs
+
+COPY ./src ./src
+
+RUN rm ./target/release/deps/backend*
+RUN cargo build --release
+
+FROM debian:bookworm-slim
+
 RUN apt-get update && \
-    apt-get install -y ffmpeg libssl3 && \
-    apt-get clean && \
+    apt-get install -y ffmpeg pkg-config libssl3 && \
     rm -rf /var/lib/apt/lists/*
-WORKDIR /app
-
-FROM runtime AS runtime-amd64
-COPY --from=builder-amd64 /app/backend .
 
-FROM runtime AS runtime-arm64
-COPY --from=builder-arm64 /app/backend .
+COPY --from=builder /backend/target/release/backend /usr/local/bin/
 
-FROM runtime-$TARGETARCH
 EXPOSE 3001
-CMD ["./backend"]
+CMD ["backend"]