…ty cell (#6941)

resolves #6937 (FR-2691)

## Summary

Clears the three header panels that used to sit above the folder table on `/data`, redistributes their responsibilities, and reshapes the "Location" column into a "Host" column that surfaces per-volume capacity info without requiring an extra click on every row.

## Changes on `/data` (`VFolderNodeListPage.tsx`)

- Removed the top `Row` that rendered the Create Folder action card, `StorageStatusPanelCard`, and `QuotaPerStorageVolumePanelCard`. The Create Folder affordance is already present as the primary button inside the folder table card header, so no replacement action card is needed.
- Promoted the folder table card to the top of the page.
- Cleaned up now-unused imports / variables (`ActionItemContent`, `BAINewFolderIcon`, `BAIAlertIconWithTooltip`, `Grid.useBreakpoint`, `useWebUINavigate`, `ErrorBoundary`, per-row `Suspense`, `CARD_MIN_HEIGHT`).

## Changes in the folder table (`VFolderNodesV2.tsx`)

- Column `title`: `data.folders.Location` (위치) → `data.Host` (호스트).
- Column header affordance: a `BAIAlertIconWithTooltip` sits next to the "Host" label. Clicking it opens the `QuotaPerStorageVolumePanelCard` in a Modal, pre-selected on a quota-supporting host. The icon is hidden entirely when no volume reports `"quota"` in `capabilities`, so the modal entry point disappears when the feature is unusable — we don't open a dialog with no useful content.
- Column cells: new `VFolderHostCell` renders a `StorageUsageBadge` (sourced from `vfolder.list_hosts()`, cached under the shared `['vhostInfo']` tan-query key that `StorageSelect` already uses) plus the host name. **No** per-cell click behavior — the modal is only reachable via the column-header affordance.
- Badge gating matches `StorageSelect`'s own precedent: the badge renders whenever the backend attaches a `usage` object (even `{}`). `StorageUsageBadge` resolves a `percentage`-less `usage` to a neutral (uncolored) marker. The accompanying tooltip reads `Host Status: <Adequate | Caution | Insufficient | Unknown>`; the `Unknown` label is a newly added key that covers the "backend reports no percentage" case.
- Switched the cell from `useSuspenseTanQuery` to `useTanQuery`. A per-cell Suspense boundary whose fallback rendered the bare host text (visually indistinguishable from the "loaded but no usage data" branch) caused rows to stick in the fallback even after `vhostInfo` resolved.

## Changes to `QuotaPerStorageVolumePanelCard.tsx`

- Dropped the outer `BAICard` wrapper and the internal title. The consumer is now a `Modal` that supplies its own title and chrome, and a nested card here produced a duplicated header on top of the modal frame.
- Moved the `?` tooltip icon (`QuestionCircleOutlined` with `data.HostDetails`) into the Modal title so all header affordances live in one place.
- `StorageSelect` moved out of the former card's `extra` slot (right-aligned, borderless) and into the modal body as the first element, left-aligned with a sensible `minWidth`.
- Added `defaultVolumeInfo?: VolumeInfo` prop. When set, the card seeds `selectedVolumeInfo` with that value and disables the built-in `autoSelectType="usage"` fallback; users can still switch volumes through the inline `StorageSelect`. This is how the header icon pre-selects a quota-supporting host.
- Props type simplified: `BAICardProps` → a dedicated local interface (card-specific passthrough props no longer make sense).

## Changes on the Dashboard (`DashboardPage.tsx`, `StorageStatusPanelCard.tsx`)

- Added a new `folderStatus` board item between `myResourceWithinResourceGroup` and `totalResourceWithinResourceGroup`, wrapped in `BAIBoardItemErrorBoundary` + `Suspense`. Invitation badge click routes to `/data?invitation=true` through `useWebUINavigate`.
- Refactored `StorageStatusPanelCard` to follow the Dashboard board-item pattern used by `MyResource` / `MyResourceWithinResourceGroup`:
  - Root is a `BAIFlex direction="column" align="stretch"` with `paddingInline: token.paddingXL` and `paddingBottom: token.padding`.
  - Title uses the shared `BAIBoardItemTitle`, which reserves space for the board's drag handle. Wrapping in a `BAICard` caused the title to overlap the handle on the left edge — that's fixed.
  - Props type: `BAICardProps` → `BAIFlexProps`.

## V2 migration notes (TODOs left in `StorageStatusPanelCard.tsx`)

The status counts still run off the legacy REST call `baiClient.vfolder.list()` and the V1 `user_resource_policy` / `project_resource_policy` GraphQL root fields. TODOs in the file call out the V2 rewrite with explicit scoping rules:

- **ProjectFolders**: when ported to `projectVfolders(projectId: …)`, it must be scoped to the project currently selected in the global header project selector (`currentProject.id`), not aggregated across every project the user can see.
- **InvitedFolders**: migration deferred. The V2 `VFolderFilter` does not yet expose an "invited only / received share" predicate, so we cannot reproduce the current `!is_owner && ownership_type === 'user'` filter with a single server-side count. Stays on legacy REST until the backend adds the filter field; revisit in a follow-up issue.

## Internationalization

Added `data.usage.Unknown` to all 21 locales under `resources/i18n/`, placed alphabetically between `StatusOfSelectedHost` and `Used` in the `data.usage` object. The key powers the tooltip fallback when a host has `usage: {}` (object present, `percentage` missing). `packages/backend.ai-ui/src/locale/*.json` is intentionally untouched — that package does not consume the key.

## Testing

- `bash scripts/verify.sh` — Relay, Lint, Format, TypeScript all pass on this branch and on every descendant branch in the stack (FR-2573, FR-2619, FR-2685, FR-2688).
- Manually verified against a manager response where every volume reports `usage: {}` (no `percentage`): per-row neutral badges render with `Host Status: Unknown` tooltip; header `?` icon appears because `icn02:flash01` / `seoul-h100:flash0*` advertise `"quota"` in capabilities; clicking it opens the modal pre-selected on the first quota-capable host.

**Checklist:** (if applicable)

- [ ] Documentation
- [ ] Minimum required manager version
- [ ] Specific setting for review (eg., KB link, endpoint or how to setup)
- [ ] Minimum requirements to check during review
- [ ] Test case(s) to demonstrate the difference of before/after