docs(ui): record common ui gap decision

docs/UI_UX_PLATFORM_CORE_MIGRATION_ROADMAP.md

@@ -37,6 +37,22 @@ Live source of truth for migrating `learning_ai_invt_trdg` UI/UX and platform cl
 | Datastore/config | Backend Cosmos repositories and `@bytelyst/config` bootstrap | `@bytelyst/datastore`, `@bytelyst/cosmos`, `@bytelyst/config`, `@bytelyst/backend-config` | Existing `@bytelyst/cosmos`/`config` usage stays; consider `datastore` only for reusable storage helpers. |
 | Operational shells/components | Local AppShell, Sidebar, cards, lists, status surfaces | `@bytelyst/ui`, `@bytelyst/dashboard-shell`, `@bytelyst/dashboard-components` | Prefer `@bytelyst/ui` first; evaluate dashboard packages only if they fit product-agnostic shell/list composition. |
 
+## Common UI Gap Closure Decision
+
+No shared `@bytelyst/ui` code change is required before the product adapter phase. The common UI package already exports the primitives required for the first product migration passes:
+
+- Controls: Button, IconButton, Input, Textarea, Select, Label, Checkbox, RadioGroup, Switch, Tabs, SegmentedControl, DropdownMenu, Tooltip, Modal, ConfirmDialog.
+- Surfaces and status: Card, Panel, Surface, Badge, StatusBadge, StatusDot, EmptyState, LoadingSpinner, Separator, StatCard.
+- Operational data: DataList, DataTable, Timeline, DiffCard, ListItemButton, Sidebar, AppShell base pieces.
+
+Verification on the common platform passed with the existing checkout:
+
+- `pnpm --filter @bytelyst/ui run build`
+- `pnpm --filter @bytelyst/ui exec eslint src --ext .ts,.tsx`
+- `git diff --check`
+
+Note: common platform had a pre-existing local modification in `packages/ui/src/components/AppShell.tsx`; this product migration did not modify or commit common-platform files.
+
 ## Roadmap
 
 | Status | Phase | Scope / Repo | Implementation Summary | Verification Commands | Commit Hash | Notes / Deferrals |