ui: marine status line in ChatShell (existing endpoints)

[Cheewye]

Summary

Adds compact "Marine Status" line in ChatShell header when in "🌊 iURi Mar" mode. Displays AIS and SignalK status from existing backend endpoints without creating new routes or pages.

Files changed

• frontend/src/components/chat/ChatShell.tsx - Added marine status fetching and display

Implementation

Status endpoints used (existing)

• AIS: /api/v1/vessels/realtime/status - Checks service_running field
• SignalK: /api/v1/marine/signalk/vessels - Uses vessels endpoint as health check (200 = ok, 503/404 = down)

Status display

• Location: Compact line below header (when chatMode === 'marine')
• Format: "Marine Status: AIS: OK/DOWN/UNKNOWN SignalK: OK/DOWN/UNKNOWN"
• Colors:
  • OK: emerald (green)
  • DOWN: rose (red)
  • UNKNOWN: slate (gray)
• Polling: Fetches on mount + every 30s (with cleanup on unmode/mount)

Behavior

• Only visible when chatMode === 'marine'
• Fetches status immediately when mode switches to marine
• Polls every 30 seconds while in marine mode
• Cleans up interval on unmount or mode switch
• Shows "unknown" if endpoint doesn't exist or fetch fails (no spam)

Verification

• cd frontend && npm ci && npm run build — PASS (✓ built in 7.93s)
• python tools/guardian_scope_check.py --base origin/main — PASS (scope check: ok)

Notes

• No new routes added
• No new pages created
• Uses only existing frontend API client (api from services/api.ts)
• Uses only existing backend endpoints (no backend work)
• No secrets, no transcript logging
• SSOT message flow unchanged

• 📋 Checklist de Seguridad iURi

Protección del Módulo Marino

• NO se modifica ni borra src/components/marine/*
• NO se introduce react-leaflet (usar MapLibre o Leaflet directo)
• Si hay WebSocket :8000 → está detrás de VITE_USE_IURI_WS flag
• NO se renombran vars: VITE_SIGNALK_WS, VITE_MQTT_WS, VITE_VESSEL_ID

Arquitectura General

• Sidebar/rutas: sin cambios (salvo que sea el objetivo del PR)
• i18n actualizado en todos los idiomas (es/pt/en/...)
• No se introducen dependencias de Three.js sin lazy-load y feature flag

Pruebas Locales

• npm run dev abre /dashboard sin errores en consola
• (Si stack marino levantado) scripts/sanity_stack.sh OK
• (Obligatorio) scripts/premerge_guard.sh PASS
• (Obligatorio) scripts/llm_diff_review.sh ejecutado (adjuntar salida)

Capturas

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🧠 Salida del Guardián IA Local

Ollama LLM Diff Review

<!-- Pegar aquí la salida de: MODEL=llama3.2 bash scripts/llm_diff_review.sh -->

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📝 Descripción de Cambios

🔗 Relacionado

Fixes #