Add per-controller-type body silhouette to GCKControllerView

[Copilot]

GCKControllerView showed no visual representation of the physical controller form factor. This PR adds SwiftUI Shape-based silhouettes that render the appropriate controller outline based on the connected type.

New: GCKControllerShape.swift

• GCKPlayStationControllerShape — bezier path outline for DualSense/DualShock (wide flat top, symmetrical bottom grips, arch gap between them)
• GCKXboxControllerShape — similar structure with a gently arched top and rounder grips matching Xbox proportions
• GCKSiriRemoteShape — tall pill (roundedRect path)
• GCKControllerShapeView — public composite view; switches on GCKControllerType?, renders the matching stroked shape, falls back to the gamecontroller SF Symbol for generic/unknown controllers

All shapes are designed in a normalised coordinate space (e.g. 200×130) and scale to any CGRect, with Color.primary stroke for automatic light/dark mode support.

Updated: GCKControllerView.swift

Embeds GCKControllerShapeView between the controller type label and the shoulder buttons:

controllerTypeLabel

GCKControllerShapeView(controllerType: GCKit.controllerType)
    .padding(.bottom, 8)

shoulder2
shoulder1

Because controllerType is @Published on the @EnvironmentObject, the silhouette updates reactively on connect/disconnect without additional wiring.

Also fixed a pre-existing typo in GCKControllerType.description: "Genric" → "Generic".