Implement Role Management Features and UI Enhancements

- Introduced a new composable `useActiveRole` for managing user roles, including fetching role status and switching roles with server validation.
- Updated `RoleSwitcher.vue` to utilize the new composable, enhancing role selection with improved error handling and UI feedback.
- Added new API endpoints for role management, including fetching user role status and switching active roles.
- Enhanced product visibility logic to filter based on the user's active role, ensuring a tailored experience.
- Updated database schema to support last active role tracking for users, improving session management.
- Refined UI components across the application to reflect role-based changes and improve user experience.

server/utils/roles.ts

@@ -120,6 +120,48 @@ export async function getVisibleProductIdsForUser(userId: string): Promise<strin
   return [...new Set(visibleProducts.map((pv) => pv.productId))]
 }
 
+/**
+ * Get products visible for a SPECIFIC role (used with RoleSwitcher)
+ * Unlike getVisibleProductIdsForUser(), this only returns products for ONE role
+ *
+ * Usage:
+ * ```typescript
+ * const activeRole = await getUserActiveRole(event)
+ * const visibleProductIds = await getVisibleProductIdsForRole(userId, activeRole)
+ * ```
+ *
+ * @param userId - The user's UUID
+ * @param roleCode - Specific role to filter by ('private', 'educator', 'company')
+ * @returns Array of product UUIDs visible for this role
+ */
+export async function getVisibleProductIdsForRole(
+  userId: string,
+  roleCode: string
+): Promise<string[]> {
+  const db = useDatabase()
+
+  // Verify user has this role (approved)
+  const hasRole = await db.query.userRoles.findFirst({
+    where: and(
+      eq(userRoles.userId, userId),
+      eq(userRoles.roleCode, roleCode),
+      eq(userRoles.status, 'approved')
+    ),
+  })
+
+  // User doesn't have this role → return empty array
+  if (!hasRole) {
+    return []
+  }
+
+  // Get all products assigned to this specific role
+  const visibleProducts = await db.query.productRoleVisibility.findMany({
+    where: eq(productRoleVisibility.roleCode, roleCode),
+  })
+
+  return visibleProducts.map((pv) => pv.productId)
+}
+
 /**
  * Assign a role to a user (MVP: manual assignment, always approved)
  * Phase 2/3: This will be replaced by role request workflow