Add stable loading skeletons for invoice and quote read views

[hammads-turing]

Summary

• add a shared read-view skeleton for ERP invoice/quote detail pages
• use the skeleton in ReadInvoiceModule and ReadQuoteModule instead of the generic page spinner
• keep quote-specific action space reserved so the layout remains stable while data loads

Validation

• attempted npm run build in idurar-erp-crm/frontend
• blocked in this workspace because vite is not installed (sh: 1: vite: not found)

Notes

• change scope is limited to idurar-erp-crm invoice/quote read flows only

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Pull Request opened by Augment Code | View session