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.

shared/types.ts

@@ -3,7 +3,7 @@
 // (The single `import type` below erases at compile time, so no runtime
 // dependency on protocol.ts is introduced — see the GameState.pendingNationOps
 // doc comment.)
-import type { NationOp } from './protocol';
+import type { NationOp, ContestedRegion } from './protocol';
 
 /** A nation's 0–100 status indices. Every value is clamped to 0–100 by the engine. */
 export interface NationStats {
@@ -474,6 +474,18 @@ export interface GameState {
    * server/db.ts) — additive, no data wipe.
    */
   seaZones: SeaZoneClaim[];
+  /**
+   * (v0.44.0, #66) Contested regions / frontlines (see {@link ContestedRegion}):
+   * one entry per region key that is a war frontline — a key in **no** nation's
+   * `territory` and not in `unowned`, contested by two or more nations at war.
+   * A region becomes contested when a turn's `contested.open` succeeds (it
+   * leaves its owner's `territory` and `unowned` — sole ownership is preserved);
+   * it is resolved (released to no man's land, or re-claimed by a party) by a
+   * later `contested.resolve`. At most ONE entry per region key (unique by
+   * `regionKey`). Always `[]` on a fresh game; rows saved before v0.44 load
+   * with this defaulted to `[]` (see server/db.ts) — additive, no data wipe.
+   */
+  contested: ContestedRegion[];
 }
 
 /**