feat: add Hono backend API server with tiered scheduler

Standalone Node.js backend that owns the SQLite database and serves
composed data via REST endpoints. Replaces the shell-scheduled scraper
with in-process node-cron tiered scheduling.

Backend structure:
- Hono HTTP server on port 3001 with CORS and request logging
- Singleton SQLite connection with WAL mode
- In-memory TTL cache for Queue-Times and fetchToday responses
- Comparison check on fetchToday (read-before-write, only upserts on change)

API endpoints:
- GET /api/calendar/week — week schedule + live ride counts for all parks
- GET /api/calendar/:parkId/month — month calendar for one park
- GET /api/parks — park list with metadata
- GET /api/parks/:id — single park detail
- GET /api/parks/:id/rides — live rides with Queue-Times/schedule fallback
- GET /api/status — health check, scrape stats
- POST /api/scrape/trigger — manual scrape (scope: today/month/upcoming/full)

Scheduler tiers:
- Tier 1: today — hourly (Mar-Dec)
- Tier 2: current month — every 6 hours
- Tier 3: upcoming — twice daily (3 AM + 3 PM)
- Tier 4: full year — daily at 3 AM

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/index.ts

@@ -0,0 +1,38 @@
+import { Hono } from "hono";
+import { serve } from "@hono/node-server";
+import { cors } from "hono/cors";
+import { logger } from "hono/logger";
+
+import { getDb } from "./db/index";
+import { startScheduler } from "./services/scheduler";
+
+import calendarRoutes from "./routes/calendar";
+import parksRoutes from "./routes/parks";
+import ridesRoutes from "./routes/rides";
+import statusRoutes from "./routes/status";
+import scrapeRoutes from "./routes/scrape";
+
+const PORT = parseInt(process.env.PORT ?? "3001", 10);
+
+const app = new Hono();
+
+app.use("*", logger());
+app.use("*", cors());
+
+app.route("/api/calendar", calendarRoutes);
+app.route("/api/parks", parksRoutes);
+app.route("/api/parks", ridesRoutes);
+app.route("/api/status", statusRoutes);
+app.route("/api/scrape", scrapeRoutes);
+
+// Initialize database on startup
+getDb();
+console.log("[backend] database initialized");
+
+// Start cron scheduler
+startScheduler();
+
+// Start HTTP server
+serve({ fetch: app.fetch, port: PORT }, (info) => {
+  console.log(`[backend] listening on http://localhost:${info.port}`);
+});