chore: gitignore generated _templ.go files, track .templ sources

Generated _templ.go files are deterministic output from .templ sources,
same as output.css from input.css. Remove them from version control to
reduce diff noise and merge conflicts. Add build:templ and live:templ
tasks to the Taskfile so generation happens as part of the build.

features/snakegame/components/board.templ

@@ -0,0 +1,113 @@
+package components
+
+import (
+	"fmt"
+
+	"github.com/ryanhamamura/c4/snake"
+)
+
+func cellSizeForGrid(width, height int) int {
+	maxDim := width
+	if height > maxDim {
+		maxDim = height
+	}
+	switch {
+	case maxDim <= 15:
+		return 28
+	case maxDim <= 20:
+		return 24
+	case maxDim <= 30:
+		return 20
+	case maxDim <= 40:
+		return 16
+	default:
+		return 14
+	}
+}
+
+type cellInfo struct {
+	snakeIdx int // -1 = empty, -2 = food
+	isHead   bool
+}
+
+templ Board(sg *snake.SnakeGame) {
+	<div
+		id="snake-board"
+		class="snake-board"
+		if sg.State != nil && (sg.Status == snake.StatusInProgress || sg.Status == snake.StatusFinished) {
+			style={ fmt.Sprintf("grid-template-columns:repeat(%d,1fr);", sg.State.Width) }
+		}
+	>
+		if sg.State != nil && (sg.Status == snake.StatusInProgress || sg.Status == snake.StatusFinished) {
+			@boardCells(sg)
+		}
+	</div>
+}
+
+templ boardCells(sg *snake.SnakeGame) {
+	{{ state := sg.State }}
+	{{ grid := buildGrid(state) }}
+	{{ cellSize := cellSizeForGrid(state.Width, state.Height) }}
+	for y := 0; y < state.Height; y++ {
+		<div class="snake-row">
+			for x := 0; x < state.Width; x++ {
+				{{ ci := grid[y][x] }}
+				if ci.snakeIdx == -2 {
+					<div class="snake-cell snake-food" style={ fmt.Sprintf("width:%dpx;height:%dpx;", cellSize, cellSize) }></div>
+				} else if ci.snakeIdx >= 0 {
+					{{ s := state.Snakes[ci.snakeIdx] }}
+					{{ bg := snakeColor(ci.snakeIdx) }}
+					if ci.isHead {
+						if s.Alive {
+							<div class="snake-cell snake-head" style={ fmt.Sprintf("width:%dpx;height:%dpx;background:%s;box-shadow:0 0 8px %s;", cellSize, cellSize, bg, bg) }></div>
+						} else {
+							<div class="snake-cell snake-head snake-dead" style={ fmt.Sprintf("width:%dpx;height:%dpx;background:%s;box-shadow:0 0 8px %s;", cellSize, cellSize, bg, bg) }></div>
+						}
+					} else {
+						if s.Alive {
+							<div class="snake-cell snake-body" style={ fmt.Sprintf("width:%dpx;height:%dpx;background:%s;", cellSize, cellSize, bg) }></div>
+						} else {
+							<div class="snake-cell snake-body snake-dead" style={ fmt.Sprintf("width:%dpx;height:%dpx;background:%s;", cellSize, cellSize, bg) }></div>
+						}
+					}
+				} else {
+					<div class="snake-cell" style={ fmt.Sprintf("width:%dpx;height:%dpx;", cellSize, cellSize) }></div>
+				}
+			}
+		</div>
+	}
+}
+
+func buildGrid(state *snake.GameState) [][]cellInfo {
+	grid := make([][]cellInfo, state.Height)
+	for y := 0; y < state.Height; y++ {
+		grid[y] = make([]cellInfo, state.Width)
+		for x := 0; x < state.Width; x++ {
+			grid[y][x] = cellInfo{snakeIdx: -1}
+		}
+	}
+	for fi := range state.Food {
+		f := state.Food[fi]
+		if f.X >= 0 && f.X < state.Width && f.Y >= 0 && f.Y < state.Height {
+			grid[f.Y][f.X] = cellInfo{snakeIdx: -2}
+		}
+	}
+	for si, s := range state.Snakes {
+		if s == nil {
+			continue
+		}
+		for bi, bp := range s.Body {
+			if bp.X >= 0 && bp.X < state.Width && bp.Y >= 0 && bp.Y < state.Height {
+				grid[bp.Y][bp.X] = cellInfo{snakeIdx: si, isHead: bi == 0}
+			}
+		}
+	}
+	return grid
+}
+
+func snakeColor(idx int) string {
+	if idx >= 0 && idx < len(snake.SnakeColors) {
+		return snake.SnakeColors[idx]
+	}
+	return "#666"
+}