docs(soft-serve): 镜像固定 v0.12.2 + 备份 sidecar + 非 root 运行 (W1N-244..248)

- 镜像 pinned charmcli/soft-serve:v0.12.2（GHCR 为 dev/nightly 源，无 v0.12.x tag）
- soft-serve-backup sidecar：每日 02:00 sqlite .backup + repos-config 打包，03:00 prune 保留 14 份
- 非 root 运行（user 1000:1000），data chown；ssh.public_url 修复
- compose 源码参考：compose/soft-serve/（服务器文件为准）

compose/soft-serve/scripts/backup.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+set -eu
+umask 077
+D() { date "+%Y-%m-%d %H:%M:%S"; }
+TS=$(date +%Y%m%d_%H%M%S)
+OUT="/backup/soft-serve_${TS}"
+mkdir -p "$OUT"
+echo "[$(D)] Starting soft-serve backup -> $OUT"
+tar czf "$OUT/repos-config.tar.gz" -C /data repos hooks config.yaml ssh
+sqlite3 /data/soft-serve.db ".backup '$OUT/soft-serve.db'"
+chmod 600 "$OUT/repos-config.tar.gz" "$OUT/soft-serve.db"
+if [ -n "${BACKUP_UID:-}" ] && [ -n "${BACKUP_GID:-}" ]; then
+  chown -R "$BACKUP_UID:$BACKUP_GID" "$OUT" /backup/backup.log
+fi
+echo "[$(D)] Backup OK: $(du -sh "$OUT" | cut -f1)"

compose/soft-serve/scripts/crontab.txt

@@ -0,0 +1,4 @@
+# Run soft-serve backup daily at 02:00
+0 2 * * * /bin/sh /scripts/backup.sh >> /backup/backup.log 2>&1
+# Prune backups older than 14 days daily at 03:00
+0 3 * * * /bin/sh /scripts/prune.sh >> /backup/backup.log 2>&1

compose/soft-serve/scripts/prune.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+set -eu
+D() { date "+%Y-%m-%d %H:%M:%S"; }
+ls -dt /backup/soft-serve_* 2>/dev/null | tail -n +15 | xargs -r rm -rf
+echo "[$(D)] Pruned. Kept $(ls -d /backup/soft-serve_* 2>/dev/null | wc -l) backups (max 14)"