feat: comprehensive balance pass (#239)

- fix: boss signature chain maintained through fight results (#148)
- fix: militia cost curve smoothed (100g -> 65g) (#145)
- fix: crystal_shard buffed to epic tier (1.65x/1.2x -> 1.9x/1.3x) (#144)
- fix: click_power recipe ceiling raised and z13-18 progression smoothed (#142)
- close: elder_bark_shield, void_fragment_amulet, soul_bound_catalyst already at target values (#143)

apps/api/src/data/adventurers.ts

@@ -21,7 +21,7 @@ export const defaultAdventurers: Array<Adventurer> = [
     unlocked:         true,
   },
   {
-    baseCost:         100,
+    baseCost:         65,
     class:            "warrior",
     combatPower:      3,
     count:            0,

apps/api/src/data/equipment.ts

@@ -269,7 +269,7 @@ export const defaultEquipment: Array<Equipment> = [
     type:     "trinket",
   },
   {
-    bonus: { clickMultiplier: 1.65, goldMultiplier: 1.2 },
+    bonus: { clickMultiplier: 1.9, goldMultiplier: 1.3 },
     description:
       "A fragment of the Mud Kraken's crystallised essence. Focuses raw power into devastating strikes.",
     equipped: false,

apps/api/src/data/recipes.ts

@@ -323,7 +323,7 @@ export const defaultRecipes: Array<CraftingRecipe> = [
 
   // Zone 13: primordial_chaos
   {
-    bonus: { type: "click_power", value: 1.2 },
+    bonus: { type: "click_power", value: 1.22 },
     description:
       "Chaos fragments and creation shards arranged into a lens that hasn't decided what it wants to focus on yet, which somehow makes every click land harder than it should.",
     id:                "chaos_lens",
@@ -387,7 +387,7 @@ export const defaultRecipes: Array<CraftingRecipe> = [
     zoneId: "reality_forge",
   },
   {
-    bonus: { type: "click_power", value: 1.22 },
+    bonus: { type: "click_power", value: 1.25 },
     description:
       "A reality shard carefully shaped with creation tools into something that could, theoretically, become a universe. Instead it makes your clicks unreasonably effective.",
     id:                "universe_seed",
@@ -439,7 +439,7 @@ export const defaultRecipes: Array<CraftingRecipe> = [
     zoneId: "primeval_sanctum",
   },
   {
-    bonus: { type: "click_power", value: 1.25 },
+    bonus: { type: "click_power", value: 1.28 },
     description:
       "The primeval relic, set into a memory shard framework. What function it originally served is unknowable. In your guild's hands, it makes every action more deliberate and more powerful.",
     id:                "first_artefact",
@@ -522,7 +522,7 @@ export const defaultRecipes: Array<CraftingRecipe> = [
 
   // Zone 18: the_absolute
   {
-    bonus: { type: "click_power", value: 1.28 },
+    bonus: { type: "click_power", value: 1.3 },
     description:
       "Absolute fragments ground and set in an omega crystal lattice — an instrument of pure finality. Every action your guild takes through it carries the weight of an ending. It does not miss.",
     id:                "absolute_focus",

apps/api/src/routes/boss.ts

@@ -9,6 +9,7 @@
 /* eslint-disable complexity -- Boss handler has inherent complexity */
 /* eslint-disable stylistic/max-len -- Long lines in combat logic */
 /* eslint-disable max-lines -- Boss route with full combat logic and helpers exceeds line limit */
+import { createHmac } from "node:crypto";
 import {
   computeSetBonuses,
   getActiveCompanionBonus,
@@ -25,6 +26,17 @@ import { updateChallengeProgress } from "../services/dailyChallenges.js";
 import { logger } from "../services/logger.js";
 import type { HonoEnvironment } from "../types/hono.js";
 
+/**
+ * Computes the HMAC-SHA256 of data using the given secret.
+ * @param data - The data string to sign.
+ * @param secret - The HMAC secret key.
+ * @returns The hex-encoded HMAC digest.
+ */
+const computeHmac = (data: string, secret: string): string => {
+  return createHmac("sha256", secret).update(data).
+    digest("hex");
+};
+
 /**
  * Exponential base for the prestige combat multiplier: Math.pow(base, prestigeCount).
  * Replaces the former linear formula (1 + count * 0.1) to enable late-game zone progression.
@@ -379,6 +391,11 @@ bossRouter.post("/challenge", async(context) => {
       where: { discordId },
     });
 
+    const secret = process.env.ANTI_CHEAT_SECRET;
+    const updatedSignature = secret === undefined
+      ? undefined
+      : computeHmac(JSON.stringify(state), secret);
+
     const { bossId } = body;
     void logger.metric("boss_challenge", 1, { bossId, discordId, won });
 
@@ -401,6 +418,9 @@ bossRouter.post("/challenge", async(context) => {
     if (casualties !== undefined) {
       response.casualties = casualties;
     }
+    if (updatedSignature !== undefined) {
+      response.signature = updatedSignature;
+    }
 
     return context.json(response);
   } catch (error) {

apps/api/test/routes/boss.spec.ts

@@ -340,6 +340,37 @@ describe("boss route", () => {
     expect(area?.status).toBe("locked");
   });
 
+  it("includes HMAC signature in response when ANTI_CHEAT_SECRET is set", async () => {
+    process.env.ANTI_CHEAT_SECRET = "test_secret";
+    const state = makeState({
+      bosses:      [makeBoss()] as GameState["bosses"],
+      adventurers: [makeAdventurer()] as GameState["adventurers"],
+      zones:       [],
+    });
+    vi.mocked(prisma.gameState.findUnique).mockResolvedValueOnce({ state } as never);
+    vi.mocked(prisma.gameState.update).mockResolvedValueOnce({} as never);
+    const res = await challenge({ bossId: "test_boss" });
+    expect(res.status).toBe(200);
+    const body = await res.json() as { signature: string | undefined };
+    expect(body.signature).toBeDefined();
+    delete process.env.ANTI_CHEAT_SECRET;
+  });
+
+  it("omits signature in response when ANTI_CHEAT_SECRET is not set", async () => {
+    delete process.env.ANTI_CHEAT_SECRET;
+    const state = makeState({
+      bosses:      [makeBoss()] as GameState["bosses"],
+      adventurers: [makeAdventurer()] as GameState["adventurers"],
+      zones:       [],
+    });
+    vi.mocked(prisma.gameState.findUnique).mockResolvedValueOnce({ state } as never);
+    vi.mocked(prisma.gameState.update).mockResolvedValueOnce({} as never);
+    const res = await challenge({ bossId: "test_boss" });
+    expect(res.status).toBe(200);
+    const body = await res.json() as { signature: string | undefined };
+    expect(body.signature).toBeUndefined();
+  });
+
   it("returns 500 when the database throws", async () => {
     vi.mocked(prisma.gameState.findUnique).mockRejectedValueOnce(new Error("DB error"));
     const res = await challenge({ bossId: "test_boss" });

apps/api/test/routes/debug.spec.ts

@@ -597,7 +597,7 @@ describe("debug route", () => {
 
     it("patches adventurer stats when only name has changed (exercises all earlier OR conditions)", async () => {
       const state = makeState({
-        adventurers: [{ id: "militia", count: 5, unlocked: true, baseCost: 100, goldPerSecond: 0.7, essencePerSecond: 0, combatPower: 3, level: 2, name: "Old Name", class: "warrior" }] as GameState["adventurers"],
+        adventurers: [{ id: "militia", count: 5, unlocked: true, baseCost: 65, goldPerSecond: 0.7, essencePerSecond: 0, combatPower: 3, level: 2, name: "Old Name", class: "warrior" }] as GameState["adventurers"],
       });
       vi.mocked(prisma.gameState.findUnique).mockResolvedValueOnce({ state } as never);
       vi.mocked(prisma.gameState.update).mockResolvedValueOnce({} as never);

apps/web/src/context/gameContext.tsx

@@ -1496,11 +1496,20 @@ export const GameProvider = ({
               });
 
               /*
-               * Boss fight modifies server state; clear stale signature so
+               * Boss fight modifies server state; update signature chain so
-               * the next pre-save or auto-save does not send a mismatched one.
+               * the next pre-save or auto-save sends the correct token.
                */
+              if (result.signature === undefined) {
                 signatureReference.current = null;
                 localStorage.removeItem("elysium_save_signature");
+              } else {
+                signatureReference.current = result.signature;
+                localStorage.setItem(
+                  "elysium_save_signature",
+                  result.signature,
+                );
+              }
+              lastSaveReference.current = Date.now();
               setAutoBossLastResult({
                 at:       Date.now(),
                 bossName: bossName,
@@ -2177,6 +2186,14 @@ export const GameProvider = ({
         }
         return applyBossResult(previous, bossId, result);
       });
+      if (result.signature === undefined) {
+        signatureReference.current = null;
+        localStorage.removeItem("elysium_save_signature");
+      } else {
+        signatureReference.current = result.signature;
+        localStorage.setItem("elysium_save_signature", result.signature);
+      }
+      lastSaveReference.current = Date.now();
       setBattleResult({ bossName: boss.name, result: result });
     } catch (error_: unknown) {
       const bossErrorMessage

packages/types/src/interfaces/api.ts

@@ -170,6 +170,11 @@ interface BossChallengeResponse {
     adventurerId: string;
     killed:       number;
   }>;
+
+  /**
+   * HMAC-SHA256 signature of the updated state for anti-cheat chain continuity.
+   */
+  signature?: string;
 }
 
 type PrestigeRequest = Record<string, never>;