chore: revert tz adjustments

Author: openscript

.changeset/rude-cooks-yell.md

@@ -0,0 +1,5 @@
+---
+"@quassel/backend": patch
+---
+
+Revert timezone adjustments

apps/backend/Dockerfile

@@ -6,12 +6,7 @@ RUN apt-get update && \
     echo "deb [signed-by=/usr/share/keyrings/postgresql.gpg] http://apt.postgresql.org/pub/repos/apt $(. /etc/os-release && echo $VERSION_CODENAME)-pgdg main" > /etc/apt/sources.list.d/pgdg.list && \
     apt-get update && \
     apt-get install -y postgresql-client-17
-RUN apt-get update && \
-    DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC \
-    apt-get install -y --no-install-recommends tzdata
 RUN apt-get clean && rm -rf /var/lib/apt/lists/*
-RUN ln -sf /usr/share/zoneinfo/Etc/UTC /etc/localtime && \
-    echo "Etc/UTC" > /etc/timezone
 ENV TZ=Etc/UTC
 ENV NODE_ENV=production
 ENV PORT=3000