Update project documentation to reflect the transition from Phase 3 to
a new critical refinement phase (Phase 3.5) and outline long-term
strategic goals.
Key documentation updates:
- Added Phase 3.5 (Essential Refinements) to the roadmap and checklist,
focusing on multi-package support, parcel invoice forms, and
internationalization (i18n).
- Defined Phase 5 (Commercialization) including tiered subscription
models (Starter, Business, Enterprise) and premium features.
- Created `IFNEX_Commercial_Model.md` to detail monetization strategies.
- Created `IFNEX_I18N_Strategy.md` to outline the multi-language
implementation approach using Polylang.
- Updated `README.md` with the revised project lifecycle and new
documentation references.
