Feat-aren/ agent status, phone prefix, wizard UX improvements

Marketplace & status:

• Add aren: 'assistant' to AGENT_SERVICE_MAP to enable status fetching on detail page
• Add fetchArenStatus in useAgentWizardStatus (GET /api/assistant/wizard/status)
• Add aren case in marketplace view to route to AAG dashboard when wizard is completed

aren-wizard/index.tsx:

• Add unsaved changes warning banner (tracks changes on informations/features/integrations steps)
• Add WizardStepSkeleton during loading/submitting states
• Fix TS7022 circular reference on getStepSnapshot return type

step-general-info.tsx:

• Auto-prepend country phone prefix to phone number field
• Phone prefix displayed as InputAdornment; national number shown separately
• Changing country updates the prefix while preserving the national number

navigation-buttons.tsx:

• Rename final step button label from "Activer l'agent" → "Créer l'agent"

step-integration-config.tsx:

• Replace MUI Select/MenuItem with CustomSelect for account dropdown
• Add paginated tab navigation (3 tabs visible at a time)
• Fix active tab index fallback when tab not found (-1 → 0)
• Add hasManyAccounts/hasNoAccounts/hasExactlyOneAccount helpers
• Fix recap card to resolve account uid from dropdown value when no explicit selection

step-resume.tsx:

• Rename SummarySection → SummaryCard (inline FC type definition)
• Remove Grid import, adjust padding/layout on summary cards