feat: #66 contested regions / frontlines — 12th ability (v0.44.0)

A third region state (contested frontline): a region in no nation's territory and not in unowned, opened/resolved by the LLM, tied to an active war. Sole-ownership invariant preserved. Durable GameState.contested; contested-inert stub; map legend stays at 7.

server/abilities/index.ts

@@ -1,8 +1,8 @@
 // The ordered LLM-ability registry.
 //
-// `ABILITIES` is the single source of truth for the 11 per-feature LLM abilities.
+// `ABILITIES` is the single source of truth for the 12 per-feature LLM abilities.
 // The engine iterates it in this order:
-//   takeovers → wars → hybrid → economy → industry → nuclear → leaders → ideology → disasters → migration → sea
+//   takeovers → wars → hybrid → economy → industry → nuclear → leaders → ideology → disasters → migration → sea → contested
 // for (a) the system-prompt schema lines + constraint bullets, (b) the per-ability
 // validate calls inside validateTurnResult, (c) the payload fields in buildUserPrompt,
 // (d) the ordered apply block inside applyTurnResult, (e) the isMeaningful check,
@@ -25,10 +25,11 @@ import { ideology } from './ideology';
 import { disasters } from './disasters';
 import { migration } from './migration';
 import { sea } from './sea';
+import { contested } from './contested';
 import type { Ability, AbilityField } from './types';
 
 /**
- * The 11 per-feature LLM abilities in their canonical apply order.
+ * The 12 per-feature LLM abilities in their canonical apply order.
  * The order matters: it determines the order of the schema lines in the
  * system prompt, the order of the validate calls, the order of the apply
  * steps, and the order of the payload fields in the user prompt. New
@@ -47,6 +48,7 @@ export const ABILITIES: readonly Ability<AbilityField>[] = [
   disasters,
   migration,
   sea,
+  contested,
 ];
 
 // ── type re-exports ────────────────────────────────────────────────────────────
@@ -173,3 +175,13 @@ export {
   isSeaZoneId,
   seaZoneName,
 } from './sea';
+
+// ── contested (frontlines) ───────────────────────────────────────────────────
+
+export {
+  validateContestedOps,
+  applyContested,
+  CONTESTED_FILL,
+  CONTESTED_STROKE,
+  contestedTooltipLabel,
+} from './contested';