Add Lambert solver, transfer matrix, Dijkstra routing, and route planner UI

- Lambert's problem solver using universal variable method with bisection
  (handles elliptic, parabolic, hyperbolic transfers + anti-podal cases)
- Transfer matrix: precompute pairwise station transfers over time window
  using Lambert solver with configurable launch velocity
- Dijkstra routing on time-expanded graph (station × week nodes, transfer
  + wait edges) to find minimum-time routes
- Route Planner UI: from/to station dropdowns, search window selector
  (1-10 years), "Find Optimal Route" button with results card
- Route visualization: orange dashed trajectory lines with arrow heads
  and leg numbers on the 2D canvas
- Tested: Mercury L1 → Jupiter L1 computes 6-month direct transfer at
  30 km/s — physically reasonable

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

frontend/src/routes/+page.svelte

@@ -7,6 +7,7 @@
 	import TimeControls from './(simulator)/components/TimeControls.svelte';
 	import ViewToggle from './(simulator)/components/ViewToggle.svelte';
 	import StationPanel from './(simulator)/components/StationPanel.svelte';
+	import RoutingPanel from './(simulator)/components/RoutingPanel.svelte';
 
 	let wasmError = $state('');
 
@@ -58,8 +59,9 @@
 				<Viewport />
 			</div>
 			<!-- Right sidebar -->
-			<aside class="w-64 shrink-0 p-2 bg-[var(--bg-secondary)] border-l border-white/5 overflow-y-auto">
+			<aside class="w-64 shrink-0 p-2 bg-[var(--bg-secondary)] border-l border-white/5 overflow-y-auto flex flex-col gap-2">
 				<StationPanel />
+				<RoutingPanel />
 			</aside>
 		{/if}
 	</main>