refactor(system-info): reduce to Stripe-style status page

Reduce admin/system-info to a single focused status view: overall
status banner, components list from existing health checks, and an
environment meta table. Drops the Modules and Permissions tabs —
those were dev-diagnostics already available via CLI.

- Remove SystemInfoService + its test; wire the action directly to
  SystemHealthService and build meta inline
- Extend SystemHealthService with per-check label + description so
  the UI speaks in customer terms while the CLI doctor path stays
  compatible
- Rebuild the view on existing app-stats-table + app-empty-state
  primitives; add a small app-status-banner component for the
  headline signal
- Align help-center nav label and i18n keys (de/en)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

i18n/default_en.json

@@ -1186,6 +1186,39 @@
   "Extend session": "Extend session",
   "Log out": "Log out",
   "System Info": "System Info",
+  "OK": "OK",
+  "System status": "System status",
+  "All systems operational": "All systems operational",
+  "Degraded service": "Degraded service",
+  "System outage detected": "System outage detected",
+  "Last checked": "Last checked",
+  "Components": "Components",
+  "Database": "Database",
+  "Database schema": "Database schema",
+  "Storage": "Storage",
+  "Administrators": "Administrators",
+  "Connection established": "Connection established",
+  "Database did not return the expected response": "Database did not return the expected response",
+  "Database check could not be executed": "Database check could not be executed",
+  "All required core tables are present": "All required core tables are present",
+  "Required core tables are missing": "Required core tables are missing",
+  "Schema check could not be executed": "Schema check could not be executed",
+  "Storage path is writable": "Storage path is writable",
+  "Storage directory is missing": "Storage directory is missing",
+  "Storage directory is not writable": "Storage directory is not writable",
+  "Storage write probe failed": "Storage write probe failed",
+  "Storage check could not be executed": "Storage check could not be executed",
+  "Baseline permissions are present": "Baseline permissions are present",
+  "Baseline permissions are missing": "Baseline permissions are missing",
+  "Permission check could not be executed": "Permission check could not be executed",
+  "At least one administrator is active": "At least one administrator is active",
+  "No active user has the administrator role": "No active user has the administrator role",
+  "Administrator check could not be executed": "Administrator check could not be executed",
+  "Scheduler is running on schedule": "Scheduler is running on schedule",
+  "Scheduler heartbeat is outdated": "Scheduler heartbeat is outdated",
+  "Scheduler has not reported yet": "Scheduler has not reported yet",
+  "Scheduler heartbeat is empty": "Scheduler heartbeat is empty",
+  "Scheduler check could not be executed": "Scheduler check could not be executed",
   "Health Status": "Health Status",
   "Check": "Check",
   "Details": "Details",