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/stub.ts

@@ -108,6 +108,13 @@ export interface StubPayload {
    * deterministicTurn), so the sea path is covered by unit tests only.
    */
   seaZones?: Array<{ zone: string; by: string }>;
+  /**
+   * (v0.44.0, #66) The currently contested regions (war frontlines,
+   * `{ regionKey, parties }`), emitted by the engine's user prompt. The stub
+   * ignores this field — it never opens or resolves a contest (see
+   * deterministicTurn), so the contested path is covered by unit tests only.
+   */
+  contested?: Array<{ regionKey: string; parties: string[] }>;
 }
 
 function truncate(s: string, n: number): string {
@@ -193,6 +200,11 @@ function truncate(s: string, n: number): string {
  * (v0.43.0, #65) The stub likewise NEVER claims, contests or re-claims a sea
  * zone (it always returns `sea: { control: [] }`) — the sea-control path is
  * covered by unit tests only, keeping the e2e assertions untouched.
+ *
+ * (v0.44.0, #66) The stub likewise NEVER opens or resolves a contested region
+ * (a war frontline) — it always returns `contested: { open: [], resolve: [] }`
+ * — the contested path is covered by unit tests only, keeping the e2e
+ * assertions untouched.
  */
 export function deterministicTurn(p: StubPayload): TurnResult {
   const state = p.state;
@@ -272,13 +284,14 @@ export function deterministicTurn(p: StubPayload): TurnResult {
     nationOps: [], // the stub never proposes nation ops (see doc comment)
   };
 
-  // The 11 ability fields, filled by the registry in its canonical order. The
+  // The 12 ability fields, filled by the registry in its canonical order. The
   // stub is ability-inert: every ability contributes its own no-op default
   // (each ability's `stub()` — see the per-ability doc comments above), so the
   // e2e assertions are unaffected. The insertion order here (ABILITIES) is the
   // historical key order pinned by the stub's deterministic output
   // (takeovers → wars → hybrid → economy → industry → nuclear → leaders →
-  // ideology → disasters → migration → sea), which must stay byte-identical.
+  // ideology → disasters → migration → sea → contested), which must stay
+  // byte-identical.
   const abilities = {} as Record<AbilityField, unknown>;
   for (const a of ABILITIES) abilities[a.field] = a.stub();