feat(docker): add safe.directory git config for git-enabled containers

Prevents "dubious ownership" errors when running git commands in containers
with mounted repositories (root user + external volume).

docker/app.Dockerfile

@@ -2,6 +2,7 @@ FROM ubuntu:24.04
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates libssl3 openssh-client procps git \
     && rm -rf /var/lib/apt/lists/*
+RUN git config --system --add safe.directory '*'
 WORKDIR /app
 COPY ./target/release/app /bin
 EXPOSE 3000

docker/githook.Dockerfile

@@ -2,6 +2,7 @@ FROM ubuntu:24.04
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates libssl3 git \
     && rm -rf /var/lib/apt/lists/*
+RUN git config --system --add safe.directory '*'
 WORKDIR /app
 COPY ./target/release/git-hook /bin
 EXPOSE 8083

docker/gitserver.Dockerfile

@@ -2,6 +2,7 @@ FROM ubuntu:24.04
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ca-certificates libssl3 git openssh-client \
     && rm -rf /var/lib/apt/lists/*
+RUN git config --system --add safe.directory '*'
 WORKDIR /app
 COPY ./target/release/gitserver /bin
 EXPOSE 8021 2222