(ui) Show retention apply details on run detail

Record planned delete counts, max-delete settings, base protection, and
ignored incomplete snapshots in retention apply results.

Surface those details on run detail pages so scheduled and manual prune
outcomes are understandable without reading the raw JSON payload.

src/pobsync_backend/tests/test_views.py

@@ -1197,9 +1197,15 @@ class ViewTests(TestCase):
                     "hint": "Check network connectivity.",
                 },
                 "prune": {
-                    "ok": False,
-                    "type": "ConfigError",
-                    "error": "Deletion blocked by --max-delete=0",
+                    "ok": True,
+                    "source": "sql",
+                    "kind": "scheduled",
+                    "planned_delete_count": 1,
+                    "max_delete": 1,
+                    "protect_bases": True,
+                    "incomplete_ignored_count": 1,
+                    "deleted": [{"dirname": "20260518-021500Z__OLD"}],
+                    "actions": ["deleted scheduled 20260518-021500Z__OLD"],
                 },
             },
         )
@@ -1211,7 +1217,11 @@ class ViewTests(TestCase):
         self.assertContains(response, "transport")
         self.assertContains(response, "Check network connectivity.")
         self.assertContains(response, "Retention")
-        self.assertContains(response, "Deletion blocked by --max-delete=0")
+        self.assertContains(response, "Planned deletions")
+        self.assertContains(response, "Max delete")
+        self.assertContains(response, "Protect bases")
+        self.assertContains(response, "Incomplete ignored")
+        self.assertContains(response, "deleted scheduled 20260518-021500Z__OLD")
 
     def test_run_detail_surfaces_host_retention_warnings(self) -> None:
         self.client.force_login(self.staff_user)