culebra: matoleo yote na matoleo ya zamani

Highlights
- Audio: a namespace of its own for sound, with or without a window. Tones, samples, streamed music and Audio.PCM (samples a script computes), Audio.Graph (native parts, worked out as they play), Audio.Capture (the microphone), and functions that measure a sound: Audio.decode, spectrum, stft/istft, resample, pitch, harmonics, loudness, integrated_loudness.
- Kauai, a language for writing music as a band plays it: a lead sheet of chords and melody, and grooves written against the chord. culebra play song.kau plays one, --wav writes it to a file, --from/--to render a part, --watch plays it again whenever a file is saved. Instruments made from recordings (a soprano and an alto saxophone) play phrase by phrase from real notes, with the tools to make more.
- LLM: a client for large language models in the standard library (LLM.ask, a conversation that keeps its history and runs the tools the model asks for, and a request sent as it is), and Http reads Server-Sent Events.
- Isolates send more: a @value or @derive instance, a class, an enum's constructor and a bound method now cross an isolate boundary, and a child's throw that cannot cross back fails the join with an error that says so.
- Dir: one trait over the places files come from. Dir.disk, Dir.memory, Dir.zip (read ZIP archives; Compress.zip writes them) and Dir.embedded; Http serves any Dir.
- XML namespace and Encoding.utf16; String.pack/String.unpack for numeric arrays and @packable records.
Changes
Breaking
- Embed.dir(name) is now Dir.embedded(name), a Dir like the others; the Embed namespace is gone. exists(""), exists(".") and exists("sub") are true for a directory that holds a file.
- Sound moved out of Canvas into Audio: Canvas.tone, Canvas.Sound, Canvas.music and the rest are now Audio.tone, Audio.Sound and Audio.music, and play with no window. Canvas forwards none of them.
- Time.parse is strict: the whole string must match, with one date, and Time.from_parts has defaults. UTC is now computed directly from the calendar in both directions.
Language / interpreter
- Names and scopes: a read that nothing visible declares is a NameError at load; if, cond and ?: arms are scopes of their own; a declaration or a defer takes no trailing if/unless; fn is declared nowhere, however a binding spells it; a typed static field is a static field.
- Types: a field's annotation is checked on every write; a built-in type's name in an annotation means that type; a Function type pattern takes a callable instance; an error's kind is a type name that takes it.
- @value and @packable classes: a field may hold the standard library's own value classes, a write that throws leaves the field as it was, and a flat class's layout is its declaration's.
- Effects and generators: a lowered body's variables get a slot each by scope; handle bodies leave only through their value; an empty handler clause is nil; fn inside a lowered frame, a defer or an effect fn names the function the user wrote.
- Errors name what went wrong more often: an unterminated string, a call on a method that is not there, a surplus positional told the keyword it was written for.
- fmt lays an array of numbers out as a table, and keeps parentheses that change meaning.
JIT / AOT / VM
- A cached JIT object is reached by a second key that holds across builds, and a hit skips the IR pipeline as well as the backend.
- The VM keeps the receiver a frame was called with, compiles MoveRetain in place of Op::Retain, and several slot and scope fixes remove lifetime bugs in closures, defaults and destructuring.
- GC: pins are counted, an object whose edges are in flux is a root, and the object registry is never more than 5/8 full.
Standard library
- Audio (above), Dir (above), XML (XML.parse, XML.events, paths with predicates, and element methods that survive isolates), LLM, Encoding.utf16, String.pack/String.unpack.
- Http: events: reads any request's answer as Server-Sent Events; srv.static serves any Dir; a streamed response is