(ops) Add terminal self-check command for native installs

Add check_pobsync_install so native deployments can run the same runtime
diagnostics from the terminal that are available in the Django Self Check view.

The command prints every check with status, returns a failing exit code when
install-critical checks fail, supports fail-on-warning for stricter automation,
and is documented in the installer output and README update flow.

README.md

@@ -137,6 +137,7 @@ loaded before Django starts:
 ```
 sudo -u pobsync pobsync-manage showmigrations pobsync_backend
 sudo -u pobsync pobsync-manage check
+sudo -u pobsync pobsync-manage check_pobsync_install
 ```
 
 The UI includes:
@@ -198,6 +199,7 @@ Then check:
 ```
 systemctl status pobsync-web pobsync-worker pobsync-scheduler
 sudo -u pobsync pobsync-manage check
+sudo -u pobsync pobsync-manage check_pobsync_install
 ```
 
 ## Development

scripts/install-systemd

@@ -586,3 +586,4 @@ echo "Useful commands:"
 echo "  systemctl status pobsync-web pobsync-worker pobsync-scheduler"
 echo "  journalctl -u pobsync-worker -f"
 echo "  sudo -u $SERVICE_USER pobsync-manage check"
+echo "  sudo -u $SERVICE_USER pobsync-manage check_pobsync_install"

src/pobsync_backend/management/commands/check_pobsync_install.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from django.core.management.base import BaseCommand, CommandError
+
+from pobsync_backend.self_check import collect_self_checks, summarize_self_checks
+
+
+class Command(BaseCommand):
+    help = "Run pobsync runtime self checks for native installs and updates."
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--fail-on-warning",
+            action="store_true",
+            help="Exit with an error when warnings are present.",
+        )
+
+    def handle(self, *args, **options):
+        checks = collect_self_checks()
+        summary = summarize_self_checks(checks)
+
+        for check in checks:
+            line = f"[{check.status.upper()}] {check.name}: {check.message}"
+            if check.detail:
+                line = f"{line} ({check.detail})"
+            if check.status == "failed":
+                self.stderr.write(line)
+            elif check.status == "warning":
+                self.stderr.write(line)
+            else:
+                self.stdout.write(line)
+
+        self.stdout.write(
+            "Summary: "
+            f"{summary['ok']} ok, "
+            f"{summary['warning']} warning(s), "
+            f"{summary['failed']} failed, "
+            f"{summary['skipped']} skipped"
+        )
+
+        if summary["failed"]:
+            raise CommandError("pobsync install self check failed.")
+        if options["fail_on_warning"] and summary["warning"]:
+            raise CommandError("pobsync install self check reported warnings.")

src/pobsync_backend/tests/test_self_check.py

@@ -1,11 +1,14 @@
 from __future__ import annotations
 
 import subprocess
+from io import StringIO
 from unittest.mock import patch
 
+from django.core.management import call_command
+from django.core.management.base import CommandError
 from django.test import SimpleTestCase
 
-from pobsync_backend.self_check import _systemd_checks
+from pobsync_backend.self_check import SelfCheck, _systemd_checks
 
 
 class SystemdSelfCheckTests(SimpleTestCase):
@@ -40,3 +43,44 @@ class SystemdSelfCheckTests(SimpleTestCase):
         journal_check = next(check for check in checks if check.name == "Journal access")
         self.assertEqual(journal_check.status, "failed")
         self.assertEqual(journal_check.message, "pobsync cannot read service logs.")
+
+
+class CheckPobsyncInstallCommandTests(SimpleTestCase):
+    def test_command_prints_summary_for_successful_checks(self) -> None:
+        stdout = StringIO()
+        stderr = StringIO()
+        checks = [
+            SelfCheck("Database connection", "ok", "django.db.backends.sqlite3"),
+            SelfCheck("Systemd services", "skipped", "systemd is not available in this runtime."),
+        ]
+
+        with patch("pobsync_backend.management.commands.check_pobsync_install.collect_self_checks", return_value=checks):
+            call_command("check_pobsync_install", stdout=stdout, stderr=stderr)
+
+        self.assertIn("[OK] Database connection", stdout.getvalue())
+        self.assertIn("[SKIPPED] Systemd services", stdout.getvalue())
+        self.assertIn("Summary: 1 ok, 0 warning(s), 0 failed, 1 skipped", stdout.getvalue())
+        self.assertEqual(stderr.getvalue(), "")
+
+    def test_command_fails_when_checks_fail(self) -> None:
+        stdout = StringIO()
+        stderr = StringIO()
+        checks = [
+            SelfCheck("POBSYNC_BACKUP_ROOT", "failed", "/backups does not exist."),
+        ]
+
+        with patch("pobsync_backend.management.commands.check_pobsync_install.collect_self_checks", return_value=checks):
+            with self.assertRaisesMessage(CommandError, "pobsync install self check failed."):
+                call_command("check_pobsync_install", stdout=stdout, stderr=stderr)
+
+        self.assertIn("[FAILED] POBSYNC_BACKUP_ROOT", stderr.getvalue())
+        self.assertIn("Summary: 0 ok, 0 warning(s), 1 failed, 0 skipped", stdout.getvalue())
+
+    def test_command_can_fail_on_warnings(self) -> None:
+        checks = [
+            SelfCheck("Global config", "warning", "Default global config has not been created yet."),
+        ]
+
+        with patch("pobsync_backend.management.commands.check_pobsync_install.collect_self_checks", return_value=checks):
+            with self.assertRaisesMessage(CommandError, "pobsync install self check reported warnings."):
+                call_command("check_pobsync_install", "--fail-on-warning", stdout=StringIO(), stderr=StringIO())