Fix problem where container home was seperate for each project dir

The problem was that we mounted `pwd` as HOME and that meant that
every time git was used it would look into the data and work for a
long time, and it would also commit everything there.

Now we have a central container-home directory in the directory
where we checked out this git repo and it is used by each session
independent of in which project directory we are.

opencode.aliases

@@ -7,10 +7,11 @@ opencode() {
     UID="$uid" \
     GID="$gid" \
     USER="$user" \
+    CONTAINER_HOME="$OPENCODE_CONTAINER_DIR/container-home" \
     docker compose \
         -f "$OPENCODE_CONTAINER_DIR/docker-compose.yaml" \
         run --rm \
         -u "$uid:$gid" \
-        opencode /home/"$user"/.opencode/bin/opencode "$@" \
+        opencode opencode "$@" \
         2> >(grep -v "No services to build" >&2)
 }