Mark action point distance helpers nodiscard (#8040)

* Mark action point distance helpers nodiscard

* Allow APD cache warmup calls

src/main/cpp/net/eagle0/shardok/library/action_point_distances/ActionPointDistances.hpp

@@ -43,7 +43,7 @@ protected:
             const std::shared_ptr<BraveableTileInfo> &braveWaterPossibleCoords,
             const std::vector<Coords> &indexToCoords,
             const std::vector<std::array<int, 6>> &adjacencyTable);
-    static auto GenerateDistances(
+    [[nodiscard]] static auto GenerateDistances(
             int fromIndex,
             const HexMap *hexMap,
             bool includeBravingWater,
@@ -51,13 +51,15 @@ protected:
             const BattalionTypeSPtr &battalionType,
             const std::shared_ptr<BraveableTileInfo> &braveWaterPossibleCoords)
             -> std::vector<DIST_T>;
-    auto BraveWaterPossibleCoords(const HexMap *hexMap) const -> std::shared_ptr<BraveableTileInfo>;
+    [[nodiscard]] auto BraveWaterPossibleCoords(const HexMap *hexMap) const
+            -> std::shared_ptr<BraveableTileInfo>;
 
     // Create coordinate lookup table for efficient index->coords conversion
-    static auto CreateIndexToCoords(const HexMap *hexMap) -> std::vector<Coords>;
+    [[nodiscard]] static auto CreateIndexToCoords(const HexMap *hexMap) -> std::vector<Coords>;
 
     // Create adjacency lookup table for efficient neighbor access
-    static auto CreateAdjacencyTable(const HexMap *hexMap) -> std::vector<std::array<int, 6>>;
+    [[nodiscard]] static auto CreateAdjacencyTable(const HexMap *hexMap)
+            -> std::vector<std::array<int, 6>>;
 
     [[nodiscard]] auto ToIndex(const Coords &coords) const -> int {
         return coords.row() * column_count + coords.column();
@@ -70,9 +72,9 @@ public:
 
     virtual ~ActionPointDistances() = default;
 
-    virtual auto Distance(int fromIndex, int toIndex) const -> DIST_T = 0;
+    [[nodiscard]] virtual auto Distance(int fromIndex, int toIndex) const -> DIST_T = 0;
 
-    virtual auto Distance(const Coords &from, const Coords &to) const -> DIST_T = 0;
+    [[nodiscard]] virtual auto Distance(const Coords &from, const Coords &to) const -> DIST_T = 0;
 };
 
 class OnDemandActionPointDistances final : public ActionPointDistances {
@@ -91,11 +93,11 @@ public:
 
     ~OnDemandActionPointDistances() override = default;
 
-    auto Distance(const int fromIndex, const int toIndex) const -> int16_t override {
+    [[nodiscard]] auto Distance(const int fromIndex, const int toIndex) const -> int16_t override {
         return distances[fromIndex].get()[toIndex];
     }
 
-    auto Distance(const Coords &from, const Coords &to) const -> int16_t override {
+    [[nodiscard]] auto Distance(const Coords &from, const Coords &to) const -> int16_t override {
         return Distance(ToIndex(from), ToIndex(to));
     }
 };

src/main/cpp/net/eagle0/shardok/library/action_point_distances/ActionPointDistancesCache.hpp

@@ -22,7 +22,7 @@ struct MapId {
     uint64_t terrainTypesId;
     uint64_t modifierId;
 
-    auto operator==(const MapId& other) const -> bool {
+    [[nodiscard]] auto operator==(const MapId& other) const -> bool {
         return terrainTypesId == other.terrainTypesId && modifierId == other.modifierId;
     }
 };
@@ -34,7 +34,7 @@ struct FullCacheKey {
     bool includeBravingWater;
     int braveWaterCost;
 
-    bool operator==(const FullCacheKey& other) const {
+    [[nodiscard]] bool operator==(const FullCacheKey& other) const {
         return mapId == other.mapId && battalionTypeId == other.battalionTypeId &&
                includeBravingWater == other.includeBravingWater &&
                braveWaterCost == other.braveWaterCost;
@@ -43,7 +43,7 @@ struct FullCacheKey {
 
 // Hash function for FullCacheKey
 struct FullCacheKeyHash {
-    size_t operator()(const FullCacheKey& key) const {
+    [[nodiscard]] size_t operator()(const FullCacheKey& key) const {
         // Pack small fields into a single 64-bit value
         uint64_t packed = (static_cast<uint64_t>(key.battalionTypeId) << 32) |
                           (static_cast<uint64_t>(key.braveWaterCost) << 1) |
@@ -85,7 +85,7 @@ private:
     // Epoch system removed - TLS cache uses size-based eviction instead
 
     // Helper to build cache key
-    static auto MakeCacheKey(
+    [[nodiscard]] static auto MakeCacheKey(
             const MapId& mapId,
             const BattalionTypeSPtr& battalionType,
             bool includeBravingWater,
@@ -107,7 +107,7 @@ public:
             bool includeBravingWater,
             int braveWaterActionPointCost = -1) -> const ActionPointDistances*;
 
-    static auto GetMapId(const HexMap* map) -> MapId;
+    [[nodiscard]] static auto GetMapId(const HexMap* map) -> MapId;
 
     // Consolidate the thread-safe cache into the persistent cache and clear
     // the current thread's local cache. This is only safe if we know reads
@@ -116,7 +116,7 @@ public:
 
     // Cache management methods
     static void ClearThreadLocalCache();
-    static size_t GetThreadLocalCacheSize();
+    [[nodiscard]] static size_t GetThreadLocalCacheSize();
 };
 
 using APDCache = std::shared_ptr<ActionPointDistancesCache>;

src/main/cpp/net/eagle0/shardok/library/action_point_distances/FixedActionPointDistances.hpp

@@ -24,7 +24,7 @@ private:
 
 public:
     // Factory method to create FixedActionPointDistances
-    static auto Create(
+    [[nodiscard]] static auto Create(
             const HexMap *map,
             const BattalionTypeSPtr &battalionType,
             bool includeBravingWater,