Add Calendar System, Forecast, and UI Overhaul

[google-labs-jules]

Implemented the requested features for the Lemonade Stand game:

1. Calendar System: Replaced "Day XX" with a specific date system (Start May 4, 2024). It correctly handles "School Mode" (May weekends only) and "Summer Mode" (Daily from mid-June).
2. Grandpa's Forecast: Added an "Ask Grandpa" button that shows a popup with a vague hint about the day's pre-rolled weather.
3. Gameplay Loop:
   • Players plan their day: check date, ask Grandpa, then decide to Open or Skip.
   • Skip Day: Advances the calendar without business. Logs missed opportunities. Penalizes >3 consecutive skips.
   • Open Stand: Runs the simulation, updates stats and money.
4. UI Overhaul:
   • New Dashboard layout with Header (Company, Date, Flavor Text) and Footer (Daily Profit).
   • Visual updates for skipped days.
   • End Game summary screen.
5. Refactoring: Completely rewrote lemonade.js into modular objects (GameState, Calendar, Simulation, UI) for better maintainability.

---

PR created automatically by Jules for task 17520935547766120919 started by @davenport651

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

---

For security, I will only act on instructions from the user who triggered this task.

New to Jules? Learn more at jules.google/docs.