[RuudBurger]

The yoga-layout WASM we ship uses sign-ext opcodes, so it only compiles on Chrome 74+. That's about 62% of webOS + Tizen devices. Chrome 57-73 is another ~21% (webOS 5 = Chrome 68, Tizen 5.0 = 63, Tizen 5.5 = 69) and those can run WASM fine, just not that build. This lowers Yoga to MVP WASM so they can lay out at all.

What changed

• Vendor a binaryen-lowered MVP build of yoga's WASM into packages/plugin-flexbox/src/yoga/vendor, generated by scripts/vendorYoga.ts (pnpm vendor:yoga). It has to be re-run after every yoga-layout bump, otherwise we keep shipping the old Yoga
• yogaVendor.spec.ts guards it: no post-MVP features in the vendored binary (and it does catch them in the upstream one), it matches the installed yoga-layout version, and it lays out a tree
• Inline worker is now built for chrome56 too, and stops using queueMicrotask and globalThis.location (both need Chrome 71, and nothing polyfills the worker)
• Second commit: the ResizeObserver shim did class extends window.ResizeObserver, which throws inside render() on Chrome < 64 (Tizen 5.0). It now falls back to a no-op base, so Lightning targets still report and DOM targets are ignored. Same file falls back to a plain rect where DOMRectReadOnly is missing (Chrome < 61). Also swapped queueMicrotask (Chrome 71) for a small helper with a promise fallback in the host config, element updates and focus, and dropped Array.prototype.at (Chrome 92) / flat (Chrome 69) on the key, focus and StyleSheet paths

Proof

• sign-ext opcodes 2 to 0, and binaryen --mvp-features validation passes
• WASM size 71,736 to 71,738 B
• Layouts identical against the upstream build
• Perf the same within noise (micro bench 603.9 vs 602.7 ms)
• New unit tests for the shim with no window.ResizeObserver / DOMRectReadOnly, and for the microtask fallback

Caveat: the plugin-flexbox dist chunk goes from 26 KB to 165 KB because Yoga is now inlined instead of imported. Should be neutral for consumers, they bundled yoga-layout's own 121 KB copy before.

Caveat: @lightningjs/renderer 3.1.1 still calls queueMicrotask itself (CoreNode, Texture), so apps still need a global polyfill for Chrome < 71. Not touching that here.

Not verified on a Chrome 57-73 device yet, only unit tests and the opcode check.

Two more commits: plugin-reanimated now goes through the exported scheduleMicrotask instead of queueMicrotask (animated styles and tracked reactions) and reads the :focus-within leaf by index instead of .at(-1), and VirtualList reads the pointer scroll hook off window / self instead of globalThis. So our own code no longer needs Chrome 71+ on any path I could find. Didn't add a global queueMicrotask polyfill for the renderer after all, because the Plex legacy builds already ship core-js's (web.queue-microtask plus es.global-this): plugin-legacy runs usage detection on the final chunks, renderer included, and on index-legacy it picks both up for chrome 53 and 56 but not for 79. core-js keeps the semantics (real microtask, a throw rethrows from the flush so it still shows up in the console). Other consumers without plugin-legacy still need their own polyfill for the renderer. Still unverified on a real Chrome 57-70 device.