feat: add equipment, achievements, and visual polish

- Equipment system: 12 items across weapon/armour/trinket slots with
  common/rare/epic/legendary rarities; starter commons auto-equipped,
  higher tiers drop from boss victories
- Achievement system: 15 milestones with typed conditions; checked
  each tick and crystal rewards applied automatically
- Achievement toast: slide-in notification, auto-dismisses after 4s
- Floating click text: +X gold floats on each manual click
- Expanded quests (9 total) and upgrades (12 total)
- Upgrade panel now shows locked upgrades so players can see their
  progression path
- formatNumber utility (K/M/B/T) used consistently across all panels
- Backfill logic for existing saves to add new content gracefully
- types package now emits .d.ts declarations

packages/types/src/index.ts

@@ -1,9 +1,15 @@
+export type {
+  Achievement,
+  AchievementCondition,
+  AchievementConditionType,
+  AchievementReward,
+} from "./interfaces/Achievement.js";
 export type { Adventurer, AdventurerClass } from "./interfaces/Adventurer.js";
 export type {
   ApiError,
   AuthResponse,
-  BossDamageRequest,
-  BossDamageResponse,
+  BossChallengeRequest,
+  BossChallengeResponse,
   LoadResponse,
   PrestigeRequest,
   PrestigeResponse,
@@ -12,6 +18,12 @@ export type {
   SaveResponse,
 } from "./interfaces/Api.js";
 export type { Boss, BossStatus } from "./interfaces/Boss.js";
+export type {
+  Equipment,
+  EquipmentBonus,
+  EquipmentRarity,
+  EquipmentType,
+} from "./interfaces/Equipment.js";
 export type { GameState } from "./interfaces/GameState.js";
 export type { Player } from "./interfaces/Player.js";
 export type { PrestigeData } from "./interfaces/Prestige.js";

packages/types/src/interfaces/Achievement.ts

@@ -0,0 +1,28 @@
+export type AchievementConditionType =
+  | "totalGoldEarned"
+  | "totalClicks"
+  | "bossesDefeated"
+  | "questsCompleted"
+  | "adventurerTotal"
+  | "prestigeCount"
+  | "equipmentOwned";
+
+export interface AchievementCondition {
+  type: AchievementConditionType;
+  amount: number;
+}
+
+export interface AchievementReward {
+  crystals?: number;
+}
+
+export interface Achievement {
+  id: string;
+  name: string;
+  description: string;
+  icon: string;
+  condition: AchievementCondition;
+  reward?: AchievementReward;
+  /** Unix timestamp when unlocked, null if not yet unlocked */
+  unlockedAt: number | null;
+}

packages/types/src/interfaces/Adventurer.ts

@@ -15,6 +15,8 @@ export interface Adventurer {
   goldPerSecond: number;
   /** Base essence generated per second */
   essencePerSecond: number;
+  /** Combat power per unit — used in boss battle simulation */
+  combatPower: number;
   count: number;
   unlocked: boolean;
 }

packages/types/src/interfaces/Api.ts

@@ -23,20 +23,37 @@ export interface LoadResponse {
   offlineSeconds: number;
 }
 
-export interface BossDamageRequest {
+export interface BossChallengeRequest {
   bossId: string;
-  damage: number;
 }
 
-export interface BossDamageResponse {
-  currentHp: number;
-  defeated: boolean;
+export interface BossChallengeResponse {
+  won: boolean;
+  partyDPS: number;
+  bossDPS: number;
+  /** Boss HP immediately before the battle */
+  bossHpBefore: number;
+  /** Boss maximum HP */
+  bossMaxHp: number;
+  /** Boss HP at end of battle before any state reset (0 on win) */
+  bossHpAtBattleEnd: number;
+  /** Boss HP stored in game after the result (0 on win, maxHp on loss) */
+  bossNewHp: number;
+  /** Total party HP at start of battle */
+  partyMaxHp: number;
+  /** Party HP remaining after battle (0 on loss) */
+  partyHpRemaining: number;
   rewards?: {
     gold: number;
     essence: number;
     crystals: number;
     upgradeIds: string[];
+    equipmentIds: string[];
   };
+  casualties?: Array<{
+    adventurerId: string;
+    killed: number;
+  }>;
 }
 
 export interface PrestigeRequest {

packages/types/src/interfaces/Boss.ts

@@ -17,6 +17,8 @@ export interface Boss {
   crystalReward: number;
   /** IDs of upgrades unlocked on defeat */
   upgradeRewards: string[];
+  /** IDs of equipment items granted on defeat */
+  equipmentRewards: string[];
   /** Minimum prestige level required to access this boss */
   prestigeRequirement: number;
 }

packages/types/src/interfaces/Equipment.ts

@@ -0,0 +1,25 @@
+export type EquipmentType = "weapon" | "armour" | "trinket";
+
+export type EquipmentRarity = "common" | "rare" | "epic" | "legendary";
+
+export interface EquipmentBonus {
+  /** Multiplier applied to all gold/s income (e.g. 1.1 = +10%) */
+  goldMultiplier?: number;
+  /** Multiplier applied to all combat power (e.g. 1.25 = +25%) */
+  combatMultiplier?: number;
+  /** Multiplier applied to click power (e.g. 1.5 = +50%) */
+  clickMultiplier?: number;
+}
+
+export interface Equipment {
+  id: string;
+  name: string;
+  description: string;
+  type: EquipmentType;
+  rarity: EquipmentRarity;
+  bonus: EquipmentBonus;
+  /** Whether the player has acquired this item */
+  owned: boolean;
+  /** Whether this item is currently equipped (only one per type can be equipped) */
+  equipped: boolean;
+}

packages/types/src/interfaces/GameState.ts

@@ -1,5 +1,7 @@
+import type { Achievement } from "./Achievement.js";
 import type { Adventurer } from "./Adventurer.js";
 import type { Boss } from "./Boss.js";
+import type { Equipment } from "./Equipment.js";
 import type { Player } from "./Player.js";
 import type { PrestigeData } from "./Prestige.js";
 import type { Quest } from "./Quest.js";
@@ -13,6 +15,8 @@ export interface GameState {
   upgrades: Upgrade[];
   quests: Quest[];
   bosses: Boss[];
+  equipment: Equipment[];
+  achievements: Achievement[];
   prestige: PrestigeData;
   /** Click power (gold per click, before upgrades) */
   baseClickPower: number;

packages/types/src/interfaces/Quest.ts

@@ -1,6 +1,6 @@
 export type QuestStatus = "locked" | "available" | "active" | "completed";
 
-export type QuestRewardType = "gold" | "essence" | "crystals" | "upgrade" | "adventurer";
+export type QuestRewardType = "gold" | "essence" | "crystals" | "upgrade" | "adventurer" | "equipment";
 
 export interface QuestReward {
   type: QuestRewardType;

packages/types/tsconfig.json

@@ -2,7 +2,8 @@
   "extends": "@nhcarrigan/typescript-config",
   "compilerOptions": {
     "outDir": "./prod",
-    "rootDir": "."
+    "rootDir": ".",
+    "declaration": true
   },
   "exclude": ["test/**/*.ts"]
 }