Lemonade Stand: browser recreation of the Atari 8-bit BASIC game

Faithful day loop - weather report, cost of lemonade rising over the
summer, glasses/signs/price decisions, thunderstorms, heat waves and
street crews - with the $$ LEMONSVILLE DAILY FINANCIAL REPORT $$ laid
out the way it printed.

The simulation is kept out of React so a season can be run headlessly:
a careful player compounds $2.00 into roughly $22 over twelve days,
while an all-in player goes broke about seven times in ten.

Weather scenes are pixel rectangles in SVG and the music is a small
chiptune engine on the Web Audio API, so there are no binary assets.
The screen is locked to a 4:3 tube and never scrolls.

README.md

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+# Lemonade Stand
+
+A browser recreation of the Atari 8-bit BASIC classic — the one you typed in,
+ran on a TV, and lost two dollars to on a cloudy day.
+
+React + TypeScript + Vite. No art assets and no audio files: the weather is
+drawn as pixel rectangles in SVG, and the music is generated by a small
+chiptune engine built on the Web Audio API.
+
+## Playing
+
+```
+npm install
+npm run dev
+```
+
+One to four players share the keyboard, hot-seat style. Each morning you see
+the weather, then decide three things: how many glasses to make, how many
+15-cent signs to put up, and what to charge. Then the town votes with its
+pocket money.
+
+- Lemonade costs 2 cents a glass on days 1–2, 4 cents through day 7, and
+  5 cents after that.
+- Everything you make is made *today*. Unsold glasses are poured away.
+- A hot, dry day brings a bigger crowd that will pay more. A heat wave is
+  better still.
+- A cloudy day can turn into a thunderstorm, and a thunderstorm ruins every
+  glass you made.
+- Street crews close the road now and then, and they tend to stay for a
+  second day.
+- Signs work, but with sharp diminishing returns — the fourth one barely
+  earns its 15 cents.
+
+You are broke when you cannot afford a single glass. Otherwise the summer runs
+as long as you like; **RETIRE** closes the books and shows the standings.
+
+## How it is put together
+
+```
+src/
+  game/       pure simulation - no React, no DOM
+    constants.ts  costs, weather profiles, the demand curve
+    engine.ts     rolls each day and settles the takings
+    reducer.ts    the day/turn state machine
+    rng.ts        seeded mulberry32, so a run can be replayed
+  audio/
+    synth.ts      pulse-wave voices, noise percussion, look-ahead sequencer
+    tunes.ts      the title, trading and closing themes
+  components/   the screens, and the CRT they are drawn on
+```
+
+The simulation is deliberately kept out of React: `engine.ts` takes a player, a
+decision and a day and hands back a `DayResult`. That is what makes it possible
+to run a few hundred seasons in a script and check that a careful player grows
+their two dollars while a reckless one goes broke about seven times in ten.
+
+### The demand curve
+
+The original BASIC listing is not reproduced line for line. `constants.ts`
+holds a reconstruction tuned to behave the way the game plays: cheap lemonade
+sells out, sales fall to nothing once the price stops being a bargain, heat
+lifts both the crowd and the price people will tolerate, and signs help a lot
+at first and hardly at all later.
+
+### The television
+
+An Atari 800 fed a 4:3 television, and a television has no scrollbar. The tube
+is locked to 4:3 and everything inside it is sized in container units, so the
+picture stays in proportion at any size. If a page ever did come out taller
+than the tube, `Fit` scales it down rather than clipping or scrolling it.
+
+## Sound
+
+Audio starts on the first click or key press, as browsers require. Two pulse
+voices, a triangle bass and filtered white noise for percussion, driven by a
+scheduler that queues notes 200 ms ahead so the music does not stutter when
+React re-renders. `MUSIC` and `SOUND` toggle independently.