Add help modal, changelog, map visits, Dockerfile, CI

- Help modal (? button or keyboard shortcut): how-to-play in Swedish,
  flavor text, full changelog sourced from src/data/version.ts
- src/data/version.ts: versioned changelog entries, in-universe Malmö voice
- Map zone clicks: each location on the Leaflet map is now clickable.
  Unlocked cult areas give resources + log entries. Locked locations show
  lore hints. 30s cooldown per location so it's a decision, not a spam button.
- Dockerfile + nginx.conf + docker-compose.yml (port 5684)
- Gitea CI workflow (identical to 2048 — derives image from repo path, needs
  TKNTKN secret, pushes :latest and :sha tags)
- README.md with mechanics summary and docker instructions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/map.ts

@@ -34,7 +34,7 @@ function dreadRadius(level: number): number {
   return [6, 10, 16, 24][Math.min(level, 3)];
 }
 
-export function initMap(containerId: string): void {
+export function initMap(containerId: string, onClick: (id: string) => void): void {
   if (!L) return;
   map = L.map(containerId, {
     center: [55.597, 13.002],
@@ -55,6 +55,7 @@ export function initMap(containerId: string): void {
       fillOpacity: 0.3,
       weight: 1,
     }).addTo(map).bindTooltip(loc.label, { className: 'map-tooltip', permanent: false });
+    m.on('click', () => onClick(loc.id));
     markers.set(loc.id, m);
   }
 }