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

apps/api/src/routes/game.ts

@@ -1,6 +1,9 @@
 import type { GameState, SaveRequest } from "@elysium/types";
 import { Hono } from "hono";
 import { prisma } from "../db/client.js";
+import { DEFAULT_ACHIEVEMENTS } from "../data/achievements.js";
+import { DEFAULT_ADVENTURERS } from "../data/adventurers.js";
+import { DEFAULT_EQUIPMENT } from "../data/equipment.js";
 import { authMiddleware } from "../middleware/auth.js";
 import { calculateOfflineGold } from "../services/offlineProgress.js";
 
@@ -18,6 +21,72 @@ gameRouter.get("/load", async (context) => {
   }
 
   const state = record.state as unknown as GameState;
+
+  let needsBackfill = false;
+
+  // Backfill combatPower on saves that predate the field
+  for (const adventurer of state.adventurers) {
+    if (adventurer.combatPower == null) {
+      const defaults = DEFAULT_ADVENTURERS.find((d) => d.id === adventurer.id);
+      adventurer.combatPower = defaults?.combatPower ?? 1;
+      needsBackfill = true;
+    }
+  }
+
+  // Backfill equipment on saves that predate the feature
+  if (!Array.isArray(state.equipment) || state.equipment.length === 0) {
+    state.equipment = structuredClone(DEFAULT_EQUIPMENT);
+    needsBackfill = true;
+  } else {
+    // Merge in any equipment items missing from existing saves (new items added later)
+    for (const defaultItem of DEFAULT_EQUIPMENT) {
+      if (!state.equipment.some((e) => e.id === defaultItem.id)) {
+        state.equipment.push(structuredClone(defaultItem));
+        needsBackfill = true;
+      }
+    }
+  }
+
+  // Backfill achievements on saves that predate the feature
+  if (!Array.isArray(state.achievements) || state.achievements.length === 0) {
+    state.achievements = structuredClone(DEFAULT_ACHIEVEMENTS);
+    needsBackfill = true;
+  } else {
+    // Merge in any achievements missing from existing saves
+    for (const defaultAchievement of DEFAULT_ACHIEVEMENTS) {
+      if (!state.achievements.some((a) => a.id === defaultAchievement.id)) {
+        state.achievements.push(structuredClone(defaultAchievement));
+        needsBackfill = true;
+      }
+    }
+  }
+
+  // Backfill equipmentRewards on bosses that predate the field
+  for (const boss of state.bosses) {
+    if (!Array.isArray(boss.equipmentRewards)) {
+      boss.equipmentRewards = [];
+      needsBackfill = true;
+    }
+  }
+
+  // Backfill new quests and upgrades from defaults (add missing ones)
+  const { DEFAULT_QUESTS } = await import("../data/quests.js");
+  const { DEFAULT_UPGRADES } = await import("../data/upgrades.js");
+
+  for (const defaultQuest of DEFAULT_QUESTS) {
+    if (!state.quests.some((q) => q.id === defaultQuest.id)) {
+      state.quests.push(structuredClone(defaultQuest));
+      needsBackfill = true;
+    }
+  }
+
+  for (const defaultUpgrade of DEFAULT_UPGRADES) {
+    if (!state.upgrades.some((u) => u.id === defaultUpgrade.id)) {
+      state.upgrades.push(structuredClone(defaultUpgrade));
+      needsBackfill = true;
+    }
+  }
+
   const now = Date.now();
 
   const { offlineGold, offlineSeconds } = calculateOfflineGold(state, now);
@@ -29,6 +98,13 @@ gameRouter.get("/load", async (context) => {
 
   state.lastTickAt = now;
 
+  if (needsBackfill || offlineGold > 0) {
+    await prisma.gameState.update({
+      where: { discordId },
+      data: { state: state as object, updatedAt: now },
+    });
+  }
+
   return context.json({ state, offlineGold, offlineSeconds });
 });