feat(ui): F8-12 — map polish (zoom invariance, labels, selection, soft radius) (#55)

* Honest pixel-space sizing for `pointRadiusPx` / `strokeWidthPx`: the
  renderer divides by the current camera scale on every
  `viewport.zoomed` so thin lines / small markers stay the same on-screen
  size at any zoom.
* Known-size planets switch to `pointRadiusWorld`, softened against the
  reference scale by `PLANET_SIZE_ZOOM_ALPHA = 0.33`; unidentified
  planets pin to a 3-px disc.
* New planet label layer renders a two-line `name / #N` legend under
  each planet (`#N` only for unidentified or when the new `planetNames`
  toggle is off). Selection now paints an inverse-fill frame around the
  selected planet's label plus an outline on the disc; the old
  selection-ring primitive is retired.
* Bombing markers swap the separate CirclePrim for a planet-outline
  overlay (damaged / wiped colour); the report deep-link moves to a
  "view bombing report" link in the planet inspector.
* Docs + tests follow: `renderer.md` reflects the new sizing contract +
  label / outline layers, vitest covers the sizing math, label
  formatting, and the new toggle, and the map-toggles e2e adds a
  persistence case for `planetNames`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/frontend/src/map/labels.ts

@@ -0,0 +1,56 @@
+// Two-line planet labels drawn on the map under each planet (F8-12 /
+// issue #55, п.29). The first line shows the planet name when known
+// and the `planetNames` toggle is on; the second line shows `#N`. For
+// unidentified or unnamed planets only the `#N` line is rendered.
+//
+// Selection is wired through `selectedPlanetId`: the renderer wraps
+// the selected planet's label in an inverse-fill frame (F8-12 / п.30)
+// instead of drawing a separate ring around the planet disc — see the
+// "label-driven selection" branch in `render.ts`.
+
+import type { GameReport } from "../api/game-state";
+
+export interface PlanetLabelData {
+	planetNumber: number;
+	x: number;
+	y: number;
+	/**
+	 * The primary line: planet name. `null` when the `planetNames`
+	 * toggle is off or the planet has no name (unidentified, or a
+	 * legacy report row with an empty string). When null the renderer
+	 * only paints the secondary `#N` line.
+	 */
+	name: string | null;
+	/** Secondary line — always present. Pre-formatted as `#N`. */
+	numberLabel: string;
+}
+
+export interface BuildPlanetLabelsOptions {
+	/** Mirrors `MapToggles.planetNames`. */
+	showNames: boolean;
+}
+
+/**
+ * buildPlanetLabels translates the report's planet list into the
+ * on-map label dataset. The toggle drives whether the name line is
+ * present; for unidentified planets the name is suppressed even when
+ * the toggle is on, because the player has no name to display.
+ */
+export function buildPlanetLabels(
+	report: GameReport,
+	opts: BuildPlanetLabelsOptions,
+): PlanetLabelData[] {
+	const out: PlanetLabelData[] = [];
+	for (const p of report.planets) {
+		const named =
+			opts.showNames && p.kind !== "unidentified" && p.name.length > 0;
+		out.push({
+			planetNumber: p.number,
+			x: p.x,
+			y: p.y,
+			name: named ? p.name : null,
+			numberLabel: `#${p.number}`,
+		});
+	}
+	return out;
+}