feat: reusable data table list view with design-token fixes

[esafwan]

Summary

• Extracts a shared, reusable DataListView component (frontend/src/components/dashboard/DataListView.tsx) generalizing the TanStack-table shape used by the Huf Data Table list and Executions pages, so future HUF list pages can reuse it.
• Fixes design-token violations in the data table list view: replaces rounded-md/bg-muted with HUF's rounded-none/border-line/bg-panel/text-steel tokens.
• Adds: column filter, column show/hide, visible row count, and wires the previously-inert search box to a real server-side search (new whitelisted get_table_records method using Frappe's search_fields/or_filters).
• Fixes user-facing copy to avoid leaking implementation details ("Search records..." / "Filter..." instead of "Search API records..." / "Filter columns locally...").

Deliberately deferred to a follow-up phase (not missed): grid/thumbnail display mode, column resize, inline cell edit, row multi-select.

Screenshot (live bench)

Test plan

• yarn typecheck — 0 errors
• yarn lint — 0 errors (60 pre-existing unrelated warnings)
• Verified live on bench (huf.localhost): search, filter, column show/hide, row count, sort all functional against the seeded Customers table
• Reviewer: confirm shared DataListView shape is suitable for later reuse by Executions.tsx (not migrated in this PR)

[esafwan]

Superseded by consolidated Data Tables PR #460, now included in integration PR #468.