ui/phase-13: planet inspector — read-only

Plumbs the map → inspector pathway: a click on a planet selects it
through the new SelectionStore, the sidebar Inspector tab swaps
its empty-state copy for a per-kind read-only field set, and a
mobile-only bottom-sheet mirrors the same content over the map.
Field projection in api/game-state.ts now surfaces every documented
planet field.

ui/frontend/src/map/render.ts

@@ -58,6 +58,18 @@ export interface RendererHandle {
 	getViewport(): Viewport;
 	getBackend(): "webgl" | "webgpu" | "canvas";
 	hitAt(cursorPx: { x: number; y: number }): Hit | null;
+	/**
+	 * onClick subscribes `cb` to a click on the map (a pointer-down /
+	 * pointer-up pair without enough drag to trigger pan). The cursor
+	 * is reported in canvas pixel coordinates so callers can hand it
+	 * straight to `hitAt`. Returns a function that detaches the
+	 * listener; the returned disposer is idempotent.
+	 *
+	 * Built on `pixi-viewport`'s `clicked` event, which already
+	 * applies the same drag threshold the pan plugin uses, so a
+	 * click here will not race a pan gesture.
+	 */
+	onClick(cb: (cursorPx: { x: number; y: number }) => void): () => void;
 	resize(widthPx: number, heightPx: number): void;
 	dispose(): void;
 }
@@ -222,6 +234,15 @@ export async function createRenderer(opts: RendererOptions): Promise<RendererHan
 		getBackend: () => rendererBackendName(app.renderer),
 		hitAt: (cursorPx) =>
 			hitTest(opts.world, handle.getCamera(), handle.getViewport(), cursorPx, mode),
+		onClick: (cb) => {
+			const handler = (e: { screen: { x: number; y: number } }): void => {
+				cb({ x: e.screen.x, y: e.screen.y });
+			};
+			viewport.on("clicked", handler);
+			return () => {
+				viewport.off("clicked", handler);
+			};
+		},
 		resize: (w, h) => {
 			app.renderer.resize(w, h);
 			viewport.resize(w, h, opts.world.width, opts.world.height);