Initial implementation of Hearts and Arrows puzzles.

Built atop Rows Garden logic as these formats are quite similar in
nature. Also fixes a bug with Rows Garden where row clues are labeled in
the grid with letters but in the clue list with numbers.

src/commonMain/kotlin/com/jeffpdavidson/kotwords/model/HeartsAndArrows.kt

@@ -0,0 +1,82 @@
+package com.jeffpdavidson.kotwords.model
+
+import com.jeffpdavidson.kotwords.formats.Puzzleable
+import kotlinx.serialization.Serializable
+import kotlin.math.floor
+import kotlin.math.roundToInt
+
+@Serializable
+data class HeartsAndArrows(
+    val title: String,
+    val creator: String,
+    val copyright: String,
+    val description: String,
+    val solutionGrid: List<List<Char>>,
+    val arrows: List<List<RowsGarden.Entry>>,
+    val light: List<RowsGarden.Entry>,
+    val medium: List<RowsGarden.Entry>,
+    val dark: List<RowsGarden.Entry>,
+    val lightHeartColor: String = "#FFFFFF",
+    val mediumHeartColor: String = "#F4BABA",
+    val darkHeartColor: String = "#E06666",
+    val addWordCount: Boolean = true,
+    val addHyphenated: Boolean = true,
+    val hasHtmlClues: Boolean = false,
+) : Puzzleable() {
+    override suspend fun createPuzzle(): Puzzle {
+        val originX = solutionGrid[0].indexOfFirst { it != '.' }
+
+        return RowsGarden.createPuzzle(
+            title = title,
+            creator = creator,
+            copyright = copyright,
+            description = description,
+            solutionGrid = solutionGrid,
+            rows = arrows,
+            light = light,
+            medium = medium,
+            dark = dark,
+            lightColor = lightHeartColor,
+            mediumColor = mediumHeartColor,
+            darkColor = darkHeartColor,
+            addWordCount = addWordCount,
+            addHyphenated = addHyphenated,
+            hasHtmlClues = hasHtmlClues,
+            rowsListTitle = "Arrows",
+            bloomsListTitle = "Hearts",
+            emptyCellType = Puzzle.CellType.VOID,
+            bloomTypeForCoordinate = { x, y ->
+                val heartTopLeft = when ((3 * y - x + originX).mod(8)) {
+                    0 -> x to y
+                    1 -> x - 2 to y - 1
+                    2 -> x - 1 to y - 1
+                    3 -> x to y - 1
+                    4 -> x - 2 to y - 2
+                    5 -> x - 1 to y - 2
+                    6 -> x to y - 2
+                    else -> x - 1 to y
+                }
+                val heartX = (heartTopLeft.first + heartTopLeft.second - originX) / 4
+                val heartY = (3 * heartTopLeft.second - heartTopLeft.first + originX) / 8
+                when ((heartX + heartY).mod(3)) {
+                    0 -> RowsGarden.BloomType.DARK
+                    1 -> RowsGarden.BloomType.LIGHT
+                    else -> RowsGarden.BloomType.MEDIUM
+                }
+            },
+            isStartOfBloom = { x, y -> (3 * y - x + originX).mod(8) == 7 },
+            getBloomCoordinates = { x, y ->
+                listOf(
+                    Puzzle.Coordinate(x = x - 1, y = y),
+                    Puzzle.Coordinate(x = x, y = y),
+                    Puzzle.Coordinate(x = x, y = y + 1),
+                    Puzzle.Coordinate(x = x + 1, y = y + 1),
+                    Puzzle.Coordinate(x = x + 1, y = y + 2),
+                    Puzzle.Coordinate(x = x, y = y + 2),
+                    Puzzle.Coordinate(x = x - 1, y = y + 2),
+                    Puzzle.Coordinate(x = x - 1, y = y + 1),
+                )
+            },
+        )
+    }
+}