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/c4game/components/board.templ

@@ -0,0 +1,65 @@
+package components
+
+import (
+	"fmt"
+
+	"github.com/ryanhamamura/c4/game"
+	"github.com/starfederation/datastar-go/datastar"
+)
+
+templ Board(g *game.Game, myColor int) {
+	<div id="c4-board" class="board">
+		for col := 0; col < 7; col++ {
+			@column(g, col, myColor)
+		}
+	</div>
+}
+
+templ column(g *game.Game, colIdx int, myColor int) {
+	if g.Status == game.StatusInProgress && myColor == g.CurrentTurn {
+		<div
+			class="column clickable"
+			data-on:click={ datastar.PostSSE("/games/%s/drop?col=%d", g.ID, colIdx) }
+		>
+			for row := 0; row < 6; row++ {
+				@cell(g, row, colIdx)
+			}
+		</div>
+	} else {
+		<div class="column">
+			for row := 0; row < 6; row++ {
+				@cell(g, row, colIdx)
+			}
+		</div>
+	}
+}
+
+templ cell(g *game.Game, row int, col int) {
+	<div class={ cellClass(g, row, col) }></div>
+}
+
+func cellClass(g *game.Game, row, col int) string {
+	color := g.Board[row][col]
+	activeTurn := 0
+	if g.Status == game.StatusInProgress {
+		activeTurn = g.CurrentTurn
+	}
+
+	class := "cell"
+	switch color {
+	case 1:
+		class += " red"
+	case 2:
+		class += " yellow"
+	}
+	if g.IsWinningCell(row, col) {
+		class += " winning"
+	}
+	if color != 0 && color == activeTurn {
+		class += " active-turn"
+	}
+	return class
+}
+
+// suppress unused import
+var _ = fmt.Sprintf