feat: add daily login bonus system with streak tracking

Awards escalating gold rewards each consecutive day (Day 7 grants bonus
crystals). Streak resets on missed days; a week multiplier boosts all
rewards for longer streaks. Shows a modal on first daily load and
displays the current streak on the character sheet.

apps/api/prisma/schema.prisma

@@ -33,6 +33,8 @@ model Player {
   lifetimeQuestsCompleted      Float @default(0)
   lifetimeAdventurersRecruited Float @default(0)
   lifetimeAchievementsUnlocked Float @default(0)
+  lastLoginDate String?
+  loginStreak   Int     @default(1)
 }
 
 model GameState {

apps/api/src/data/loginBonus.ts

@@ -0,0 +1,19 @@
+export interface DayReward {
+  day: number;
+  goldBase: number;
+  crystals?: number;
+}
+
+/**
+ * Rewards for days 1–7 of a login streak. The cycle repeats every 7 days
+ * with a multiplier equal to the week number (week 1 = ×1, week 2 = ×2, etc.).
+ */
+export const DAILY_REWARDS: DayReward[] = [
+  { day: 1, goldBase: 500 },
+  { day: 2, goldBase: 1_000 },
+  { day: 3, goldBase: 2_500 },
+  { day: 4, goldBase: 5_000 },
+  { day: 5, goldBase: 10_000 },
+  { day: 6, goldBase: 25_000 },
+  { day: 7, goldBase: 50_000, crystals: 5 },
+];

apps/api/src/routes/game.ts

@@ -1,4 +1,4 @@
-import type { GameState, SaveRequest } from "@elysium/types";
+import type { GameState, LoginBonusResult, SaveRequest } from "@elysium/types";
 import { computeSetBonuses } from "@elysium/types";
 import { createHmac } from "node:crypto";
 import { Hono } from "hono";
@@ -11,6 +11,7 @@ import { DEFAULT_EQUIPMENT } from "../data/equipment.js";
 import { DEFAULT_EQUIPMENT_SETS } from "../data/equipmentSets.js";
 import { DEFAULT_EXPLORATIONS } from "../data/explorations.js";
 import { INITIAL_EXPLORATION } from "../data/initialState.js";
+import { DAILY_REWARDS } from "../data/loginBonus.js";
 import { DEFAULT_QUESTS } from "../data/quests.js";
 import { authMiddleware } from "../middleware/auth.js";
 import { getOrResetDailyChallenges } from "../services/dailyChallenges.js";
@@ -357,7 +358,10 @@ gameRouter.use("*", authMiddleware);
 gameRouter.get("/load", async (context) => {
   const discordId = context.get("discordId") as string;
 
-  const record = await prisma.gameState.findUnique({ where: { discordId } });
+  const [record, playerRecord] = await Promise.all([
+    prisma.gameState.findUnique({ where: { discordId } }),
+    prisma.player.findUnique({ where: { discordId } }),
+  ]);
 
   if (!record) {
     return context.json({ error: "No save found" }, 404);
@@ -644,6 +648,44 @@ gameRouter.get("/load", async (context) => {
   // Generate or reset daily challenges if a new day has begun
   state.dailyChallenges = getOrResetDailyChallenges(state);
 
+  // Daily login bonus — award once per calendar day (UTC)
+  const todayUTC = new Date().toISOString().slice(0, 10);
+  const yesterdayUTC = new Date(now - 86_400_000).toISOString().slice(0, 10);
+  let loginBonus: LoginBonusResult | null = null;
+  let loginStreak = playerRecord?.loginStreak ?? 1;
+
+  if (playerRecord && playerRecord.lastLoginDate !== todayUTC) {
+    const prevStreak = playerRecord.loginStreak ?? 0;
+    const newStreak = playerRecord.lastLoginDate === yesterdayUTC ? prevStreak + 1 : 1;
+    const dayIndex = (newStreak - 1) % 7;
+    const weekMultiplier = Math.floor((newStreak - 1) / 7) + 1;
+    const reward = DAILY_REWARDS[dayIndex];
+    const goldEarned = (reward?.goldBase ?? 500) * weekMultiplier;
+    const crystalsEarned = ((reward?.crystals ?? 0) * weekMultiplier);
+
+    state.resources.gold = Math.min(state.resources.gold + goldEarned, RESOURCE_CAP);
+    state.player.totalGoldEarned += goldEarned;
+    state.resources.crystals = Math.min(state.resources.crystals + crystalsEarned, RESOURCE_CAP);
+
+    loginStreak = newStreak;
+    loginBonus = {
+      streak: newStreak,
+      goldEarned,
+      crystalsEarned,
+      day: dayIndex + 1,
+      weekMultiplier,
+    };
+    needsBackfill = true;
+
+    await prisma.player.update({
+      where: { discordId },
+      data: { lastLoginDate: todayUTC, loginStreak: newStreak },
+    }).catch((err: unknown) => {
+      const code = (err as { code?: string }).code;
+      if (code !== "P2034") throw err;
+    });
+  }
+
   state.lastTickAt = now;
 
   if (needsBackfill || offlineGold > 0 || offlineEssence > 0) {
@@ -660,7 +702,7 @@ gameRouter.get("/load", async (context) => {
 
   const secret = process.env.ANTI_CHEAT_SECRET;
   const signature = secret ? computeHmac(JSON.stringify(state), secret) : undefined;
-  return context.json({ state, offlineGold, offlineEssence, offlineSeconds, signature });
+  return context.json({ state, offlineGold, offlineEssence, offlineSeconds, signature, loginBonus, loginStreak });
 });
 
 gameRouter.post("/save", async (context) => {