[damarals]

Closes #32

Summary

• Adds a fixed search TextInput to the unified deck page (app/deck/[id].tsx) that lives inside the FlatList's ListHeaderComponent, so it scrolls with the list rather than floating.
• Live-filters the merged kept/dropped row list by case-insensitive substring match against artist OR title, composed on top of the existing kept/skipped pill filter.
• Adds a "No cards match '<query>'" empty-state row, shown only when the query is non-empty.

Implementation notes

• Filter chain: (filter === 'all' ? rows : rows.filter(r => r.kind === filter)).filter(r => rowMatchesQuery(r, needle)). Existing pill semantics preserved; search composes on top.
• Single helper rowMatchesQuery(row, needle) covers both kept (Card) and dropped (DroppedTrack) rows since both share artist/title fields, so the dropped-tracks list is filtered by the same pass through the unified DeckRow[].
• Search input kept inline (not extracted to a CardSearchInput atom): only one usage, no reuse value.
• Design tokens: bg-navy800 (Tailwind class wired to tokens.colors.navy800), tokens.colors.navy50 for input text, Nunito_600SemiBold 13px (matches the body weight loaded in app/_layout.tsx; Nunito_500Medium is not loaded).
• Filter is purely visual: editingIsrc is keyed by ISRC, so year-override edits still apply correctly to filtered-out cards. PDF export and drops state are untouched.
• Kept pill block remains gated on hasDrops (the existing droppedCount > 0 semantics) — only the ListHeaderComponent wrapper is now always rendered (to host the search input).

Test plan

• npm run typecheck clean
• npm run lint clean
• npm test — 143/143 passing
• Manual: open a deck, type a query, confirm live filter on artist and title (case-insensitive), clearing restores list.
• Manual: with drops present, confirm pill + search compose (e.g., kept + "queen").
• Manual: with drops present, confirm dropped-tracks rows are filtered by the same query.
• Manual: type a non-matching query, confirm No cards match "..." row appears.
• Manual: edit a year override on a card; with that card filtered out, confirm the override still persisted.