fix: resolve pre-existing TypeScript strictness build errors

- Add @types/node to API devDependencies
- Create HonoEnv type and apply to all routers + auth middleware for
  proper context.get/set("discordId") typing
- Use conditional spreads for exactOptionalPropertyTypes dailyChallenges
  in GameContext, tick engine, and prestige route
- Use conditional spread for optional signature in SaveRequest calls
- Add non-null assertions in shuffle/template index for noUncheckedIndexedAccess
- Cast GameState to never for Prisma InputJsonValue fields
- Exclude vite.config.ts from web tsconfig (it runs in Node context)

apps/api/src/routes/prestige.ts

@@ -1,5 +1,6 @@
 import type { BuyPrestigeUpgradeRequest, GameState, PrestigeRequest } from "@elysium/types";
 import { Hono } from "hono";
+import type { HonoEnv } from "../types/hono.js";
 import { prisma } from "../db/client.js";
 import { authMiddleware } from "../middleware/auth.js";
 import { DEFAULT_PRESTIGE_UPGRADES } from "../data/prestigeUpgrades.js";
@@ -10,7 +11,7 @@ import {
   isEligibleForPrestige,
 } from "../services/prestige.js";
 
-export const prestigeRouter = new Hono();
+export const prestigeRouter = new Hono<HonoEnv>();
 
 prestigeRouter.use("*", authMiddleware);
 
@@ -55,7 +56,7 @@ prestigeRouter.post("/", async (context) => {
   // Preserve daily challenges across the prestige reset and apply any crystal rewards
   const finalState: GameState = {
     ...newState,
-    dailyChallenges: updatedDailyChallenges,
+    ...(updatedDailyChallenges !== undefined ? { dailyChallenges: updatedDailyChallenges } : {}),
     resources: {
       ...newState.resources,
       crystals: newState.resources.crystals + challengeCrystals,