Refactor database schema for roles and visibility management

- Updated the roles table to use `code` as the primary key, enhancing readability and simplifying junction tables.
- Modified `user_roles` and `product_role_visibility` tables to reference `role_code` instead of `role_id`, maintaining many-to-many relationships.
- Added foreign key constraints and created new indexes to optimize queries.
- Removed the previous migration file that was no longer needed, ensuring a cleaner migration history.
- Updated related documentation to reflect the new schema changes and their benefits.

tasks/00-PROGRESS.md

@@ -2,9 +2,9 @@
 
 ## my.experimenta.science
 
-**Last Updated:** 2025-11-01
+**Last Updated:** 2025-11-03
 **Overall Progress:** 39/137 tasks (28.5%)
-**Current Phase:** ✅ Phase 3 - Authentication (Validated & Completed)
+**Current Phase:** ✅ Phase 3 - Authentication (Completed) | Database Schema Refinement Completed
 
 ---
 
@@ -30,6 +30,29 @@
 
 ## 🚀 Current Work
 
+**Phase:** Database Schema Refinement ✅ **COMPLETED** (2025-11-03)
+
+**Recent Work: Roles Table Refactoring**
+
+Completed a major database schema refinement to improve code readability and performance:
+
+- ✅ **Refactored `roles` table**: Changed Primary Key from `id` (UUID) to `code` (enum: 'private' | 'educator' | 'company')
+- ✅ **Updated junction tables**: `user_roles.roleCode` and `product_role_visibility.roleCode` now reference `roles.code` directly
+- ✅ **Simplified code**: Removed all UUID lookup queries for roles - direct enum usage throughout
+- ✅ **Maintained functionality**: Many-to-Many relationships fully preserved
+- ✅ **Migration**: Successfully applied, database reseeded with 3 roles, 3 products, 7 role assignments
+- ✅ **Auto-assignment**: Confirmed that new users automatically receive `'private'` role on first login
+- ✅ **Product visibility**: Verified role-based product filtering works correctly
+- ✅ **Documentation**: Updated CLAUDE.md and ARCHITECTURE.md to reflect new schema
+
+**Benefits:**
+- Better readability: `roleCode: 'private'` instead of `roleId: 'uuid...'`
+- Simpler code: No role lookups needed
+- Better performance: Fewer joins in queries
+- Type safety: Direct enum type usage
+
+---
+
 **Phase:** Phase 3 - Authentication ✅ **VALIDATED & COMPLETED** (2025-11-01)
 
 **Validation Summary:**
@@ -431,6 +454,7 @@ Tasks:
 | 2025-10-30 | 15.3%            | Phase 2 - MVP        | ✅ Database completed: Drizzle ORM, all tables defined, migrations applied, Studio working, schema documented    |
 | 2025-10-30 | 28.5%            | Phase 3 - MVP        | ✅ Authentication completed: Password Grant Flow, JWT validation, auth endpoints, UI components, middleware      |
 | 2025-11-01 | 28.5%            | Phase 3 - Validation | ✅ Authentication validated: Login tested with Playwright, DB user creation verified, docs updated              |
+| 2025-11-03 | 28.5%            | DB Refinement        | ✅ Roles table refactored: `code` as PK, simplified junction tables, maintained Many-to-Many functionality      |
 
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