feat: native yoga-layout via taffy + JSON module imports — ink #348 end-to-end

[proggeramlug]

Summary

Makes ink (React-based TUI) compile and render fully natively — no WASM yoga, no V8. Three independent changes under #348.

╭──────────────────────────────────────╮
│                                      │
│ Native ink via taffy                 │
│                                      │
│ left col            right col        │
│                                      │
╰──────────────────────────────────────╯

(render(<App/>) → positioned ANSI from a single native executable.)

1. Native perry/yoga backend over taffy

yoga-layout (the WASM flexbox engine ink uses for geometry) is replaced by a native backend on taffy 0.7 (already a perry-runtime dep).

• crates/perry-runtime/src/yoga.rs — handle-based node store with the full FFI surface ink uses (node new/free, insert/remove/child-count, set number/edge/gap/enum, measure-func register/unregister, calculateLayout, computed box/edge getters). calculateLayout builds a fresh TaffyTree, wires per-node measure callbacks back into JS via js_native_call_value, and runs compute_layout_with_measure. A GC root scanner marks live measure callbacks.
• crates/perry-codegen/src/lower_call/native_table/yoga.rs — 14 NativeModSig rows → runtime entry points (registered in native_table/mod.rs).
• perry/yoga added to the perry-namespace module list in perry-api-manifest.
• node_modules/yoga-layout/src/index.ts is a thin shim re-exporting the native primitives behind the real yoga Node/Config API.

2. JSON module imports → native default export

import data from "./x.json" (with or without with { type: "json" }) was skipped entirely during module collection, leaving the default import bound to the empty-module sentinel. ink's cli-boxes (import cliBoxes from "./boxes.json") thus resolved to undefined, and <Box borderStyle="round"> threw Cannot read properties of undefined (reading 'topLeft').

collect_modules.rs now materializes a JSON import as a native ESM module: validate as JSON, then compile export default <json>; through the normal parse → lower → codegen path. Non-JSON modules take an identical code path (the change only removes is_json from a disjunction that was already false for them). Malformed JSON now fails with a clear Failed to parse JSON module … error.

3. Labeled break from a nested switch

A labeled switch didn't register its label as a break target, so break <label>; from a nested switch (react-reconciler's createFiberFromTypeAndProps) escaped to the wrong exit — dropping Context.Provider children, so ink rendered nothing. switch_stmt.rs now registers the consumed label like loops already did.

Testing

• Native taffy layout (direct): root 80x5, child positioning, measure callbacks all correct.
• JSON import (minimal): import boxes from './data.json' → boxes.round.topLeft === '╭'.
• ink end-to-end: borderless + borderStyle="round", flexDirection row/column, padding/margin/width/justifyContent all lay out via taffy and render positioned ANSI (exit 0).
• cargo test --bin perry green; cargo build --release green.

Depends on #5024 (function-prototype own-key tracking), already merged.

Known follow-up (separate, minor)

<Text dimColor> renders as [object Object] (boolean style-modifier handling in ink's Text); color= works. Filed separately.

Closes #348.