fix(dbbackup): 缺 MinecraftServer 导出时重试、CLI 失败退出、面板与 watchdog 告警，异地快照要求完整

docs/openapi.yaml

@@ -363,7 +363,8 @@ components:
               description: Bundle file name, felis-db-<UTC stamp>-<label>.tar.
             label:
               type: string
-              enum: [daily, pre-migrate, pre-restore, manual]
+              enum: [daily, pre-migrate, pre-restore, offsite, manual]
+              description: offsite is the bundle `felis offsite sync` takes after copying world archives; a restore records the newest bundle on disk, which may be one.
             size_bytes:
               type: integer
               format: int64
@@ -375,6 +376,12 @@ components:
             dir:
               type: string
               description: Backup directory on the host.
+            servers_error:
+              type: string
+              description: >
+                Why the bundle lacks the MinecraftServer objects (the cluster did not
+                answer the export), when it does. A restore from it brings back the
+                database but no servers.
         stale:
           type: boolean
           description: True when there is no record or it is older than max_age_seconds.

docs/troubleshooting.md

@@ -2020,7 +2020,7 @@ along). One bundle is `felis-db-<UTC stamp>-<label>.tar`:
 | `MANIFEST.json` | version, schema version, `pg_dump --version`, sha256 of every member |
 | `db.dump` | `pg_dump --format=custom` of the `felis` database |
 | `state/etc/felis/...` | every file in `/etc/felis`: `secrets.env` (DB password, session/forwarding secrets, registry tokens), `felis.host.toml`, `felis.pod.toml`, the `felis.toml` symlink, `offsite.env` (bucket credentials and encryption key), `smtp-password`, `uploads-s3-access-key` and `uploads-s3-secret-key` (the mail relay password and the uploads bucket keys `felis setup` took), the panel TLS pair, and the installer's own markers (`system-server-images`, `velocity.fingerprint`). `bootstrap.done` is left out on purpose |
-| `k8s/minecraftservers.json` | every MinecraftServer, status and server-side metadata stripped, ready for `kubectl apply` (best effort: when the cluster did not answer, the manifest records why) |
+| `k8s/minecraftservers.json` | every MinecraftServer, status and server-side metadata stripped, ready for `kubectl apply`. The export is tried 3 times, 10 s apart; when the cluster still does not answer, the bundle is written without it and the manifest records why (next section) |
 
 next to a `.sha256` sidecar in `sha256sum` format. **A bundle contains the
 secrets; treat it like `/etc/felis` itself.** Retention per label: `daily` 14
@@ -2056,6 +2056,22 @@ sudo journalctl -u felis-db-backup -n 50 --no-pager   # why the last run failed
 sudo felis db backup                                  # take one now (label manual)
 ```
 
+**A bundle without the MinecraftServer objects.** When the cluster does not
+answer the export (`k3s kubectl get minecraftservers`) three times running,
+the bundle is still written, since it holds the database, but a restore from it
+brings back no servers. `felis db backup` then exits 1 (the timer's run shows
+failed) after `wrote ...` and the reason; the panel card turns amber
+(**不完整**) with the reason and the commands; the watchdog mails the owners
+(`the newest control-plane database backup ... lacks the MinecraftServer
+objects`) while that bundle is the newest; `felis db verify` and
+`felis offsite list`/`fetch-db` name the gap. A pre-migrate or pre-restore
+bundle goes the same way without stopping the upgrade or the restore, whose
+rollback needs the database alone. The bundle the off-site copy takes after
+copying archives refuses to go without them and is tried again next pass. Once
+`sudo k3s kubectl get minecraftservers -A` answers, run `sudo felis db backup`.
+[GO-TESTED: `internal/dbbackup`, `cmd/felis`, `internal/watchdog`; the panel card
+in `DBBackupCard.test.tsx`]
+
 Common failures: felis-postgres not running (`kubectl exec` reports no running
 pod, or `pg_dump: ... connection refused`; next section); `k3s: executable file not
 found` from a `felis` that runs with neither `/usr/local/bin` on PATH nor k3s
@@ -2303,6 +2319,12 @@ host yourself, plus the off-site encryption key if the copy is in the bucket.
    tar -xOf felis-db-....tar k8s/minecraftservers.json | kubectl apply -f -
    ```
 
+   When `tar` answers `Not found in archive`, the bundle lacks the
+   MinecraftServer objects (`fetch-db` said so when it fetched it). Fetch the
+   newest bundle `felis offsite list` shows without `no MinecraftServer
+   objects` and apply its `k8s/minecraftservers.json` instead; servers that
+   bundle does not list do not come back from it.
+
 7. Bring the world archives back into the archive volume:
 
    ```