Tasks

• [x] Add filterText state + Input to Board component header
• [x] Filter byCol entries by title/name/token (case-insensitive substring match)
• [x] Add showArchived toggle (default: true) to show/hide the archived column
• [x] Bypass filter when hash token is present in URL (so deep-linked items open)
• [x] Add "no matches" empty state when filter yields zero results
• [x] Test: filter by title narrows cards across all columns
• [x] Test: archived toggle hides/shows archived column
• [x] Test: hash deep-link still opens detail dialog when filter is active