feat(#56): War as a first-class state — declare/end ops, mutual-defense drag-in, relation sync

Promote the bare 'war' relation to a named War entity in GameState.wars:
- War: { id, sides[], declaredTurn, declaredDate?, aims?, status, front? }
- TurnResult.wars: { declare: WarDeclareOp[], end: WarEndOp[] }
- syncWarRelations: derive 'war' from active wars, fallback to 'hostile' on end
- Mutual-defense drag-in: belligerent allies added to sides (one level)
- Bare 'war' back-compat: never downgraded, never force-created
- Stub: empty wars (e2e unaffected); ~30 new unit tests

v0.33.0

AGENTS.md

@@ -327,6 +327,29 @@ history/
   `server/protocol.test.ts`, `server/db.test.ts`, `server/regions.test.ts`,
   `scripts/region-geo.test.ts`). **PR 1 of 2 — deliberately NOT deployed** (the user deploys
   when PR 2, the per-region LLM lever, ships).
+- **Wars — `GameState.wars`, a first-class conflict entity (v0.33, #56).**
+  Since v0.33 the `war` relation is no longer a bare boolean flag but a named `War` entity in
+  `GameState.wars` (required, `[]` at creation; a legacy SQLite row without the field loads as
+  `[]` — additive, never wipes). Each `War` has a stable id (`w1`, `w2`, …), a `sides` list
+  (≥2 distinct nation ids — any two distinct members are at war with each other), `declaredTurn`,
+  `declaredDate`, optional `aims`, a `status` (`active` / `armistice` / `capitulation`), and an
+  optional `front` (region keys). `TurnResult.wars = { declare: WarDeclareOp[]; end: WarEndOp[] }`
+  (both required, default `[]`): a **declare** creates a new active `War` (sides resolved via
+  `resolveNationRef` — id first, then case-insensitive unique name; a declare with <2 resolved
+  distinct sides is dropped); an **end** finds a war by id (unknown → no-op, never throw) and sets
+  its `status` to the outcome (`armistice` or `capitulation`). After declare/end,
+  `syncWarRelations(prev, next)` enforces the derived `war` relation: any two nations on opposite
+  sides of ≥1 **active** war get `war` in both directions (overriding lesser statuses — you
+  cannot "make peace" without ending the war); when a war ends, the pairs it caused that are not
+  covered by another active war fall back to `hostile`. A **bare** `war` relation with no matching
+  active war (legacy/back-compat) is never downgraded and never force-created. **Mutual-defense
+  drag-in**: when a war is declared, each belligerent's `ally`-relation partners are added to the
+  war's `sides` (one level, no cascade; deterministic — sides in declared order, allies in sorted
+  id order). The system prompt documents the field + declare/end ops (at most 1–2 declarations
+  per turn, each narrated in `events`); `buildUserPrompt` carries the current **active** wars
+  (as `WarInfo[]`: id + sides + aims) so the model can `end` by id. The **stub never declares or
+  ends** a war (`wars: { declare: [], end: [] }`) — e2e (CI, `LLM_STUB=1`) is unaffected and the
+  path is unit-tested only (`server/engine.test.ts`).
 - **Map click → dossier target (owner resolved from the RegionMap, by region key).**
   Clicking a sub-region does NOT open a popup — it switches the dossier to that sub-region's
   owning nation (`focusNation(ownerId, {name})` in `App.tsx`, which also records which region was