feat: add quick search filter for database rows by title

[zacharias-ona]

Description

Database views support filtering by property values via the filter bar, but there's no quick way to search/filter rows by title text. In Notion, the filter bar includes a search input that instantly narrows visible rows by matching against the row title. For databases with many rows, this is the fastest way to find a specific entry without setting up a formal filter rule.

This adds a search input to the database toolbar that client-side filters rows by title substring match (case-insensitive). It complements the existing filter engine without replacing it.

Acceptance Criteria

• A search input appears in the database toolbar (next to filter/sort buttons)
• Typing in the search input filters visible rows by case-insensitive title substring match
• Search works across all view types (table, board, list, calendar, gallery)
• Search combines with existing filters (AND logic — rows must match both search text and active filters)
• Clearing the search input restores all rows
• Search state is local (not persisted to view config) — it resets on view switch or page navigation
• Search input has a magnifying glass icon and placeholder text "Search..."
• Storybook stories cover the search input in the toolbar
• E2E test verifies search filtering in table view
• pnpm lint && pnpm typecheck && pnpm test pass

Dependencies

None

Technical Notes

• The filter engine in src/components/database/hooks/use-database-filters.ts already produces filteredRows. Add a second filtering step for the search text, or integrate into the existing useMemo chain in database-view-client.tsx.
• Row titles come from row.title (the page title of the row page). This is already available in the row data passed to views.
• Keep this client-side only — no new API calls or database queries needed.
• Place the search input in the toolbar area defined in database-view-client.tsx, near the existing filter/sort buttons.
• Use shadcn/ui Input component with a search icon from lucide-react.
• Reference .agents/design.md for input styling (sharp corners, muted placeholder text).

Approval Required

This is a HIGH risk enhancement because it adds new interactive UI to the database toolbar, which has been a high-churn area (20+ UI regression bugs in the last 7 days). The toolbar layout, filter interaction, and view-switching logic are tightly coupled. Comment "approved" to release to the automation queue.

[Siddhant-K-code]

approved

[Siddhant-K-code]

New input detected. This issue will be triaged on the next Feature Planner run.

[Siddhant-K-code]

Maintainer input received. Issue is now in the automation queue.