🐛 Fix silent download failure and cosmetic naming bugs 🐛

Fixes three bugs discovered during live container testing.
The critical bug was a bash post-increment no-op: `exitCode=$((exitCode++))`
assigns the *old* value back to the variable, so exitCode stays 0 even
when a download fails. This caused the Docker build to succeed silently
when the gitea binary download failed, publishing a broken image to Docker Hub.
- rootfs/root/docker/setup/05-custom.sh: change exitCode=$((exitCode++)) to
exitCode=$((exitCode + 1)) in both the gitea and act_runner failure handlers
- rootfs/usr/local/bin/entrypoint.sh: change CONTAINER_NAME and description
from "archlinux" (copied template default) to "gitea"
- rootfs/usr/local/etc/docker/init.d/08-gitea.sh: remove leading space from
[ -d " /config/ssh" ] path test so the directory existence check is correct

.claude/
rootfs/root/docker/setup/05-custom.sh
rootfs/usr/local/bin/entrypoint.sh
rootfs/usr/local/etc/docker/init.d/08-gitea.sh

rootfs/usr/local/etc/docker/init.d/08-gitea.sh

@@ -322,7 +322,7 @@ __update_conf_files() {
 
 	# - - - - - - - - - - - - - - - - - - - - - - - - -
 	# define actions
-	[ -d " /config/ssh" ] || mkdir -p "/config/ssh"
+	[ -d "/config/ssh" ] || mkdir -p "/config/ssh"
 	[ -d "$DATA_DIR/ssh" ] || mkdir -p "$DATA_DIR/ssh"
 	[ "$COPY_SSHD_CONF" = "yes" ] && copy "/etc/ssh/sshd_config" "/config/ssh/"
 	if [ ! -f "/config/ssh/ssh_host_ed25519_key" ]; then