Fix save/resume after refresh + map basemap

Map (basemap was rendering black):
- Inline MapLibre style (dark-navy background + subtle OpenFreeMap ne2sr
  raster) instead of the remote "dark" style, whose vector tiles are empty at
  world zoom and gated the choropleth on a remote styledata fetch.
- Explicit prod worker URL (maplibre-gl-worker via ?url) so GeoJSON sources
  process in the production bundle.
- Hardened the choropleth against geo load-order races (empty sources up
  front, ownership stamped once data lands) and bumped fill opacity so the
  vivid per-nation colors are the star on the non-black background.

Save/resume (a refresh used to drop users to the home screen):
- Persist the active game id in localStorage (history.activeGameId) on create
  and resume; clear it when explicitly starting a new game.
- Auto-resume the last game on a page refresh (GET /api/games/:id + /map),
  re-attaching the SSE stream; fall back to home gracefully if it's gone.
- Home screen: prominent "Resume last game" button + a "Saved games" section
  (newest first). New GET /api/games list endpoint.

e2e: two new deterministic tests — auto-resume-on-reload and explicit resume
from the home screen (both under LLM_STUB=1).

Quality gates: typecheck, lint, 21 unit tests, 3 e2e tests — all pass.

src/components/PresetPicker.tsx

@@ -1,16 +1,37 @@
+import { Play } from 'lucide-react';
 import { Badge } from './ui/badge';
 import { Button } from './ui/button';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from './ui/card';
 import type { PresetMeta } from '@shared/types';
+import type { GameSummary } from '@shared/protocol';
 
 interface Props {
   presets: PresetMeta[];
   loading?: boolean;
   onPlay: (presetId: string) => void;
+  /** Recent saved games (newest-updated first) for the "Saved games" section. */
+  savedGames?: GameSummary[];
+  /** The id remembered as the active game (drives the "Resume last game" button). */
+  activeGameId?: string | null;
+  /** Resume a saved game by id (shared by the resume button and saved-games rows). */
+  onResume?: (id: string) => void;
 }
 
-/** Home screen: a grid of scenario cards, each with a Play button. */
-export default function PresetPicker({ presets, loading, onPlay }: Props) {
+/**
+ * Home screen: a grid of scenario cards (each with a Play button), a prominent
+ * "Resume last game" affordance, and a "Saved games" section listing prior
+ * games so the user can get back into one.
+ */
+export default function PresetPicker({
+  presets,
+  loading,
+  onPlay,
+  savedGames = [],
+  activeGameId,
+  onResume,
+}: Props) {
+  const activeGame = activeGameId ? savedGames.find((g) => g.id === activeGameId) : undefined;
+
   return (
     <div className="mx-auto max-w-6xl px-6 py-10">
       <header className="mb-8">
@@ -20,6 +41,30 @@ export default function PresetPicker({ presets, loading, onPlay }: Props) {
           world turn by turn — the LLM is the world engine.
         </p>
       </header>
+
+      {/* Resume last game — prominent, shown whenever a game is remembered. */}
+      {activeGameId && onResume && (
+        <div
+          data-testid="resume-bar"
+          className="mb-8 rounded-xl border border-primary/30 bg-primary/5 p-3"
+        >
+          <Button
+            data-testid="resume-last"
+            className="w-full justify-between"
+            onClick={() => onResume(activeGameId)}
+            disabled={loading}
+          >
+            <span className="flex items-center gap-2">
+              <Play className="size-4" />
+              Resume last game
+            </span>
+            <span className="text-sm font-normal text-muted-foreground">
+              {activeGame ? `${activeGame.presetTitle} · ${activeGame.date}` : 'Pick up where you left off'}
+            </span>
+          </Button>
+        </div>
+      )}
+
       <div className="grid gap-5 sm:grid-cols-2 lg:grid-cols-3">
         {presets.map((p) => (
           <Card
@@ -44,6 +89,42 @@ export default function PresetPicker({ presets, loading, onPlay }: Props) {
           </Card>
         ))}
       </div>
+
+      {/* Saved games: get back into any prior game. */}
+      {savedGames.length > 0 && (
+        <section className="mt-12" data-testid="saved-games">
+          <h2 className="mb-4 text-xl font-bold tracking-tight">Saved games</h2>
+          <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
+            {savedGames.map((g) => (
+              <Card
+                key={g.id}
+                className="flex flex-col"
+                data-testid="saved-game"
+              >
+                <CardHeader>
+                  <div className="flex items-start justify-between gap-2">
+                    <CardTitle className="text-base">{g.presetTitle}</CardTitle>
+                    <Badge variant="secondary" className="shrink-0 text-xs">
+                      {g.date}
+                    </Badge>
+                  </div>
+                  <CardDescription className="text-sm">Turn {g.turn}</CardDescription>
+                </CardHeader>
+                <CardContent className="mt-auto">
+                  <Button
+                    variant="secondary"
+                    className="w-full"
+                    onClick={() => onResume?.(g.id)}
+                    disabled={loading}
+                  >
+                    Resume
+                  </Button>
+                </CardContent>
+              </Card>
+            ))}
+          </div>
+        </section>
+      )}
     </div>
   );
 }