ui/phase-16: cargo routes inspector + map pick foundation

Add per-planet cargo routes (COL/CAP/MAT/EMP) to the inspector with
a renderer-driven destination picker (faded out-of-reach planets,
cursor-line anchor, hover-highlight) and per-route arrows on the
map. The pick-mode primitives are exposed via `MapPickService` so
ship-group dispatch in Phase 19/20 can reuse the same surface.

Pass A — generic map foundation:
- hit-test now sizes the click zone to `pointRadiusPx + slopPx` so
  the visible disc is always part of the target.
- `RendererHandle` gains `onPointerMove`, `onHoverChange`,
  `setPickMode`, `getPickState`, `getPrimitiveAlpha`,
  `setExtraPrimitives`, `getPrimitives`. The click dispatcher is
  centralised: pick-mode swallows clicks atomically so the standard
  selection consumers do not race against teardown.
- `MapPickService` (`lib/map-pick.svelte.ts`) wraps the renderer
  contract in a promise-shaped `pick(...)`. The in-game shell
  layout owns the service so sidebar and bottom-sheet inspectors
  see the same instance.
- Debug-surface registry exposes `getMapPrimitives`,
  `getMapPickState`, `getMapCamera` to e2e specs without spawning a
  separate debug page after navigation.

Pass B — cargo-route feature:
- `CargoLoadType`, `setCargoRoute`, `removeCargoRoute` typed
  variants with `(source, loadType)` collapse rule on the order
  draft; round-trip through the FBS encoder/decoder.
- `GameReport` decodes `routes` and the local player's drive tech
  for the inline reach formula (40 × drive). `applyOrderOverlay`
  upserts/drops route entries for valid/submitting/applied
  commands.
- `lib/inspectors/planet/cargo-routes.svelte` renders the
  four-slot section. `Add` / `Edit` call `MapPickService.pick`,
  `Remove` emits `removeCargoRoute`.
- `map/cargo-routes.ts` builds shaft + arrowhead primitives per
  cargo type; the map view pushes them through
  `setExtraPrimitives` so the renderer never re-inits Pixi on
  route mutations (Pixi 8 doesn't support that on a reused
  canvas).

Docs:
- `docs/cargo-routes-ux.md` covers engine semantics + UI map.
- `docs/renderer.md` documents pick mode and the debug surface.
- `docs/calc-bridge.md` records the Phase 16 reach waiver.
- `PLAN.md` rewrites Phase 16 to reflect the foundation + feature
  split and the decisions baked in (map-driven picker, inline
  reach, optimistic overlay via `setExtraPrimitives`).

Tests:
- `tests/map-pick-mode.test.ts` — pure overlay-spec helper.
- `tests/map-cargo-routes.test.ts` — `buildCargoRouteLines`.
- `tests/inspector-planet-cargo-routes.test.ts` — slot rendering,
  picker invocation, collapse, cancel, remove.
- Extensions to `order-draft`, `submit`, `order-load`,
  `order-overlay`, `state-binding`, `inspector-planet`,
  `inspector-overlay`, `game-shell-sidebar`, `game-shell-header`.
- `tests/e2e/cargo-routes.spec.ts` — Playwright happy path: add
  COL, add CAP, remove COL, asserting both the inspector and the
  arrow count via `__galaxyDebug.getMapPrimitives()`.

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

ui/frontend/src/routes/games/[id]/+layout.svelte

@@ -65,6 +65,10 @@ fresh.
 		ORDER_DRAFT_CONTEXT_KEY,
 		OrderDraftStore,
 	} from "../../../sync/order-draft.svelte";
+	import {
+		MAP_PICK_CONTEXT_KEY,
+		MapPickService,
+	} from "$lib/map-pick.svelte";
 	import {
 		GALAXY_CLIENT_CONTEXT_KEY,
 		GalaxyClientHolder,
@@ -101,6 +105,13 @@ fresh.
 	setContext(RENDERED_REPORT_CONTEXT_KEY, renderedReport);
 	const galaxyClient = new GalaxyClientHolder();
 	setContext(GALAXY_CLIENT_CONTEXT_KEY, galaxyClient);
+	// `MapPickService` lives at the layout so both the active map
+	// view (which binds the renderer-side resolver) and the
+	// inspector subsections (which call `pick(...)`) see the same
+	// instance via context — they sit on sibling branches of the
+	// component tree.
+	const mapPick = new MapPickService();
+	setContext(MAP_PICK_CONTEXT_KEY, mapPick);
 
 	// selectedPlanet resolves the current selection against the live
 	// report so both the desktop sidebar and the mobile sheet display
@@ -120,6 +131,13 @@ fresh.
 	const localShipClass = $derived(
 		renderedReport.report?.localShipClass ?? [],
 	);
+	const inspectorPlanets = $derived(renderedReport.report?.planets ?? []);
+	const inspectorRoutes = $derived(renderedReport.report?.routes ?? []);
+	const inspectorMapWidth = $derived(renderedReport.report?.mapWidth ?? 1);
+	const inspectorMapHeight = $derived(renderedReport.report?.mapHeight ?? 1);
+	const inspectorLocalDrive = $derived(
+		renderedReport.report?.localPlayerDrive ?? 0,
+	);
 
 	// Reveal the inspector whenever a new planet selection lands.
 	// Reading `selection.selected` once outside the effect keeps the
@@ -228,6 +246,11 @@ fresh.
 	<PlanetSheet
 		planet={selectedPlanet}
 		{localShipClass}
+		routes={inspectorRoutes}
+		planets={inspectorPlanets}
+		mapWidth={inspectorMapWidth}
+		mapHeight={inspectorMapHeight}
+		localPlayerDrive={inspectorLocalDrive}
 		onMap={effectiveTool === "map"}
 		onClose={() => selection.clear()}
 	/>