i18n(frontend): the System status panel's service names and status texts are hardcoded English in useSystemStatus #18353

Found during Refined UI step 2 (#18240). The step-2 System status panel (components/layout/SystemStatusModal.vue, built on the kit BaseModal) renders strings that autobot-frontend/src/composables/useSystemStatus.ts produces in English with no i18n:

• service display names, :122-131 ('Backend API', 'Browser Service', 'AI Stack (ChromaDB)' …);
• the default and unknown rows, :135-141, :258-260, :309-310 (statusText: 'Running' | 'Connected' | 'Status Unknown');
• getSystemStatusTooltip :410-416 ('Click to view system issues' …), and getSystemStatusText / getSystemStatusDescription.

The file is also 622 lines, over the 600 limit.

Acceptance Criteria

• Every user-visible string from useSystemStatus comes from i18n keys, translated in all 11 locales (the composable returns keys or params, and the panel translates them)
• useSystemStatus.ts is ≤ 600 lines, split by concern rather than by an arbitrary cut
• Tests cover the status-to-text mapping in at least two locales
• The i18n untranslated ratchet does not rise