feat(29-02): create GearImage component for fit-within rendering

Renders images with object-contain by default (letterbox/pillarbox),
object-cover when cover prop is set, or CSS transform when crop
values are present. Parent container uses dominant color background.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/components/GearImage.tsx

@@ -0,0 +1,65 @@
+interface GearImageProps {
+	src: string;
+	alt: string;
+	dominantColor?: string | null;
+	cropZoom?: number | null;
+	cropX?: number | null;
+	cropY?: number | null;
+	className?: string;
+	cover?: boolean;
+}
+
+export function GearImage({
+	src,
+	alt,
+	dominantColor,
+	cropZoom,
+	cropX,
+	cropY,
+	className = "",
+	cover = false,
+}: GearImageProps) {
+	const hasCrop = cropZoom != null && cropZoom > 1;
+
+	if (cover) {
+		return (
+			<img
+				src={src}
+				alt={alt}
+				className={`w-full h-full object-cover ${className}`}
+			/>
+		);
+	}
+
+	if (hasCrop) {
+		return (
+			<img
+				src={src}
+				alt={alt}
+				className={`w-full h-full object-cover ${className}`}
+				style={{
+					transform: `scale(${cropZoom}) translate(${cropX ?? 0}%, ${cropY ?? 0}%)`,
+					transformOrigin: "center center",
+				}}
+			/>
+		);
+	}
+
+	return (
+		<img
+			src={src}
+			alt={alt}
+			className={`w-full h-full object-contain ${className}`}
+		/>
+	);
+}
+
+/**
+ * Returns the background color for an image container.
+ * Uses the dominant color if available, otherwise a neutral fallback.
+ */
+export function imageContainerBg(
+	dominantColor?: string | null,
+): string | undefined {
+	return dominantColor || "#f3f4f6";
+}