(bugfix) Surface rsync SSH failure details in run results

Include the selected SSH credential metadata and rsync log tail in
dry-run and failed backup results so Django shows the actual SSH or
rsync failure instead of only the exit code.

Warn in host checks when a host still uses database-stored private key
material, making it easier to spot old credentials after switching to
generated filesystem keys.

src/pobsync_backend/config_source.py

@@ -41,6 +41,13 @@ def _attach_credential_options(config: dict[str, Any], credential: SshCredential
     if paths.get("known_hosts") and not _has_ssh_option(options, "UserKnownHostsFile"):
         options.append(f"-oUserKnownHostsFile={paths['known_hosts']}")
     ssh["options"] = options
+    config["ssh_credential"] = {
+        "id": credential.pk,
+        "name": credential.name,
+        "identity_file": paths["identity_file"],
+        "generated": credential.generated,
+        "storage": "filesystem" if credential.key_path else "database",
+    }
 
 
 def _materialize_credential(credential: SshCredential) -> dict[str, str]:

src/pobsync_backend/host_ops.py

@@ -53,6 +53,15 @@ def collect_host_checks(host: HostConfig, global_config: GlobalConfig | None = N
             checks.append(
                 _host_path_check("Host SSH key file", key_path, must_exist=True, must_be_writable=False, must_be_readable=True)
             )
+        elif credential.private_key:
+            checks.append(
+                SelfCheck(
+                    "Host SSH key storage",
+                    "warning",
+                    "Selected credential stores private key material in the database.",
+                    "Generated filesystem keys are recommended for native systemd installs.",
+                )
+            )
 
     host_root = resolve_host_root(global_config.backup_root, host.host)
     checks.append(_host_path_check("Host backup root", host_root, must_exist=True, must_be_writable=True))

src/pobsync_backend/tests/test_django_config_source.py

@@ -90,6 +90,7 @@ class DjangoConfigSourceTests(TestCase):
         self.assertIn("-oBatchMode=yes", cfg["ssh"]["options"])
         self.assertIn(f"-oIdentityFile={identity_file}", cfg["ssh"]["options"])
         self.assertIn(f"-oUserKnownHostsFile={known_hosts}", cfg["ssh"]["options"])
+        self.assertEqual(cfg["ssh_credential"]["storage"], "database")
 
     def test_host_ssh_credential_overrides_global_credential(self) -> None:
         global_credential = SshCredential.objects.create(name="global-key", private_key="GLOBAL")
@@ -133,3 +134,4 @@ class DjangoConfigSourceTests(TestCase):
             cfg = DjangoConfigSource().effective_config_for_host("web-01")
 
         self.assertIn(f"-oIdentityFile={identity_file}", cfg["ssh"]["options"])
+        self.assertEqual(cfg["ssh_credential"]["storage"], "filesystem")

src/pobsync_backend/tests/test_run_scheduled_config_source.py

@@ -49,6 +49,24 @@ class RunScheduledConfigSourceTests(SimpleTestCase):
         self.assertEqual(result["host"], "web-01")
         run_rsync.assert_called_once()
 
+    def test_failed_dry_run_includes_log_tail(self) -> None:
+        def fake_run_rsync(command, log_path, timeout_seconds):
+            log_path.parent.mkdir(parents=True, exist_ok=True)
+            log_path.write_text("Permission denied (publickey).\nrsync error\n", encoding="utf-8")
+            return RsyncResult(exit_code=12, command=command)
+
+        with patch("pobsync.commands.run_scheduled.run_rsync", side_effect=fake_run_rsync):
+            result = run_scheduled(
+                prefix=Path("/missing-prefix"),
+                host="web-01",
+                dry_run=True,
+                config_source=FakeConfigSource(),
+            )
+
+        self.assertFalse(result["ok"])
+        self.assertEqual(result["rsync"]["exit_code"], 12)
+        self.assertEqual(result["rsync"]["log_tail"], ["Permission denied (publickey).", "rsync error"])
+
     def test_successful_real_run_applies_prune_when_requested(self) -> None:
         with TemporaryDirectory() as tmp:
             prefix = Path(tmp) / "home"