Hashing decimal numbers is wrong

Composites with different decimal numbers hash to the same value: ```ts const c1 = Composite({ a: 2.0 }); const c2 = Composite({ a: 2.5 }); assert(!Composite.equal(c1, c2)); // fails ``` The reason for this is that the implementation in `MurmurHashStream.update` only hashes 4 bytes but Javascript numbers are 8 bytes: ```ts case "number": this._writeByte(chunk & 0xff); this._writeByte((chunk >>> 8) & 0xff); this._writeByte((chunk >>> 16) & 0xff); this._writeByte((chunk >>> 24) & 0xff); return; ``` I tried to fix this by hashing all 8 bytes in a similar way: ```ts case "number": this._writeByte(chunk & 0xff); this._writeByte((chunk >>> 8) & 0xff); this._writeByte((chunk >>> 16) & 0xff); this._writeByte((chunk >>> 24) & 0xff); this._writeByte((chunk >>> 32) & 0xff); this._writeByte((chunk >>> 40) & 0xff); this._writeByte((chunk >>> 48) & 0xff); this._writeByte((chunk >>> 56) & 0xff); return; ``` But that doesn't work because JS bitwise operations only work on 32-bit integers so it converts `chunk` to a 32 bit int and hence this doesn't work. GPT-5 found this to work: ```ts // Allocate these once, outside the hot path const buf = new ArrayBuffer(8) // dv and u8 are 2 different views on the same buffer `buf` const dv = new DataView(buf) const u8 = new Uint8Array(buf) export class MurmurHashStream implements Hasher { // ... update(chunk: symbol | string | number | bigint): void { switch (typeof chunk) { // ... case "number": dv.setFloat64(0, chunk, true) // fixed little-endian this._writeByte(u8[0]!) this._writeByte(u8[1]!) this._writeByte(u8[2]!) this._writeByte(u8[3]!) this._writeByte(u8[4]!) this._writeByte(u8[5]!) this._writeByte(u8[6]!) this._writeByte(u8[7]!) return ```