Fix off-by-one errors in board and promotion click mapping

internal/client/screens/localmoveinput.go

@@ -19,6 +19,7 @@ type LocalMoveInput struct {
 	pendingPromoFrom chess.Square
 	pendingPromoTo   chess.Square
 	promoPopupY      int
+	boardOriginY     int
 	flipped          bool
 }
 
@@ -43,6 +44,13 @@ func (li *LocalMoveInput) SetPromoPopupY(y int) {
 	li.promoPopupY = y
 }
 
+// SetBoardOriginY records the terminal row at which the board's top cell is
+// drawn, so mouse clicks can be translated into board coordinates. Screens that
+// render content (e.g. a title) above the board must set this to that offset.
+func (li *LocalMoveInput) SetBoardOriginY(y int) {
+	li.boardOriginY = y
+}
+
 // PendingPromo reports whether a promotion selection is awaiting user input.
 func (li *LocalMoveInput) PendingPromo() bool {
 	return li.pendingPromo
@@ -153,6 +161,7 @@ func (li *LocalMoveInput) handleSquareClick(sq chess.Square, board *render.Board
 func (li *LocalMoveInput) squareFromMouse(x, y int, board *render.Board) (chess.Square, bool) {
 	cellCols := board.CellCols()
 	cellRows := board.CellRows()
+	y -= li.boardOriginY
 	if x < 2 || x > 2+8*cellCols-1 || y < 0 || y > 8*cellRows-1 {
 		return 0, false
 	}
@@ -224,7 +233,9 @@ func (li *LocalMoveInput) promoSAN(key string, game *chess.Game) string {
 func (li *LocalMoveInput) handlePromoClick(x, y int, board *render.Board, game *chess.Game) string {
 	cols := board.CellCols()
 	rows := board.CellRows()
-	pieceY := li.promoPopupY + 2
+	// promoPopupY is the row of the "Promote pawn:" label; the piece cells are
+	// drawn on the rows immediately below it.
+	pieceY := li.promoPopupY + 1
 	if y < pieceY || y >= pieceY+rows {
 		return ""
 	}

internal/client/screens/localmoveinput_test.go

@@ -123,6 +123,30 @@ func TestLocalMoveInput_HandleMsg_MouseClickSelectsPiece(t *testing.T) {
 	}
 }
 
+func TestLocalMoveInput_HandleMsg_BoardOriginY_OffsetsClick(t *testing.T) {
+	// Screens like puzzle/replay draw a title before the board, so the board's
+	// top cell is at terminal row 2. With cellRows=3, e2 (cellRow 6) is drawn at
+	// rows 18,19,20 in board-local space, i.e. terminal rows 20,21,22. Clicking
+	// the bottom of that cell (row 22) must still resolve to E2, not the square
+	// below it. This is the off-by-one regression.
+	game := chess.NewGame()
+	board := render.NewBoard(game.Position(), false)
+	li := NewLocalMoveInput(false)
+	li.SetBoardOriginY(2)
+	// Bottom row of the e2 cell: x=26, board-local y=20 → terminal y=22.
+	msg := tea.MouseMsg{X: 26, Y: 22, Action: tea.MouseActionPress, Button: tea.MouseButtonLeft}
+	san, handled, _ := li.HandleMsg(msg, board, game)
+	if !handled {
+		t.Fatalf("expected handled=true for click on board")
+	}
+	if san != "" {
+		t.Fatalf("expected empty san on first click, got %q", san)
+	}
+	if !li.hasSelected || li.selectedSq != chess.E2 {
+		t.Fatalf("expected selectedSq=E2 after clicking bottom of e2 cell, got selected=%v sq=%v", li.hasSelected, li.selectedSq)
+	}
+}
+
 func TestLocalMoveInput_HandleMsg_MouseClick_ConvertsToSAN(t *testing.T) {
 	game := chess.NewGame()
 	board := render.NewBoard(game.Position(), false)
@@ -201,6 +225,55 @@ func TestLocalMoveInput_HandleMsg_PromoMode_QSelectsQueen(t *testing.T) {
 	}
 }
 
+func TestLocalMoveInput_HandlePromoClick_TopPieceRowSelectsQueen(t *testing.T) {
+	// The popup is laid out as: row promoPopupY = "Promote pawn:", then the
+	// piece cells on rows promoPopupY+1 .. promoPopupY+cellRows. Clicking the
+	// FIRST piece row (promoPopupY+1) on the queen (leftmost, x=2) must select
+	// the queen. This is the vertical off-by-one regression.
+	fen, _ := chess.FEN("3k4/4P3/8/8/8/8/8/4K3 w - - 0 1")
+	game := chess.NewGame(fen)
+	board := render.NewBoard(game.Position(), false)
+	li := NewLocalMoveInput(false)
+	li.pendingPromo = true
+	li.pendingPromoFrom = chess.E7
+	li.pendingPromoTo = chess.E8
+	li.SetPromoPopupY(26)
+	// Top piece row, queen column: x=2, y=27.
+	click := tea.MouseMsg{X: 2, Y: 27, Action: tea.MouseActionPress, Button: tea.MouseButtonLeft}
+	san, handled, _ := li.HandleMsg(click, board, game)
+	if !handled {
+		t.Fatalf("expected handled=true for click on promo popup")
+	}
+	if san != "e8=Q+" && san != "e8=Q" {
+		t.Fatalf("expected queen promo SAN from top piece row, got %q", san)
+	}
+	if li.pendingPromo {
+		t.Fatalf("expected pendingPromo cleared after selection")
+	}
+}
+
+func TestLocalMoveInput_HandlePromoClick_LabelRowIsNotAPiece(t *testing.T) {
+	// The key-label row below the pieces (promoPopupY+cellRows+1) must NOT
+	// register as a piece selection.
+	fen, _ := chess.FEN("3k4/4P3/8/8/8/8/8/4K3 w - - 0 1")
+	game := chess.NewGame(fen)
+	board := render.NewBoard(game.Position(), false)
+	li := NewLocalMoveInput(false)
+	li.pendingPromo = true
+	li.pendingPromoFrom = chess.E7
+	li.pendingPromoTo = chess.E8
+	li.SetPromoPopupY(26)
+	// cellRows defaults to 3, so the label row is at 26+3+1 = 30.
+	click := tea.MouseMsg{X: 2, Y: 30, Action: tea.MouseActionPress, Button: tea.MouseButtonLeft}
+	san, _, _ := li.HandleMsg(click, board, game)
+	if san != "" {
+		t.Fatalf("expected no promo selection on label row, got %q", san)
+	}
+	if !li.pendingPromo {
+		t.Fatalf("expected pendingPromo to remain set after clicking label row")
+	}
+}
+
 func TestLocalMoveInput_HandleMsg_PromoMode_EscCancels(t *testing.T) {
 	fen, _ := chess.FEN("3k4/4P3/8/8/8/8/8/4K3 w - - 0 1")
 	game := chess.NewGame(fen)

internal/client/screens/puzzle.go

@@ -1,4 +1,4 @@
 package screens
 
 import (
 	"fmt"
@@ -516,6 +516,8 @@
 	var sb strings.Builder
 	sb.WriteString(puzzleTitleStyle.Render("Puzzle Mode"))
 	sb.WriteString("\n\n")
+	// Title on line 0, blank on line 1, so the board's top cell is on line 2.
+	m.input.SetBoardOriginY(2)
 	boardView := m.board.View()
 	right := m.rightPanel()
 	sb.WriteString(lipgloss.JoinHorizontal(lipgloss.Top, boardView, "  ", right))

internal/client/screens/replay.go

@@ -407,6 +407,8 @@ func (m *ReplayModel) View() string {
 	var sb strings.Builder
 	sb.WriteString(replayTitleStyle.Render("Replay"))
 	sb.WriteString("\n\n")
+	// Title on line 0, blank on line 1, so the board's top cell is on line 2.
+	m.input.SetBoardOriginY(2)
 	boardView := m.board.View()
 	moveView := m.moveList.View()
 	left := boardView