Web SDK runtime gotchas

Linked from AGENTS.md. Hard-won WASM/browser-runtime bugs and workarounds that aren't obvious from reading the TypeScript alone. See bindings/web/AGENTS.md for the SDK's general architecture and build/test commands.

• Cross-origin isolation. SharedArrayBuffer requires COOP/COEP headers (the minimal example's vite.config.ts sets these). Safari additionally needs the coi-serviceworker.js polyfill.
• VLM Worker crash recovery. If rac_vlm_component_process causes a WASM OOM ("memory access out of bounds"), the Worker auto-recovers by creating a fresh WASM instance on the next process() call rather than staying wedged.
• Qwen2-VL WebGPU workaround. Qwen2-VL models produce NaN logits on WebGPU due to f16 M-RoPE overflow. The VLM Worker forces CPU WASM for Qwen2-VL even when WebGPU is otherwise active for the session.
• Struct offsets are never hard-coded. TypeScript never bakes in C struct field offsets. wasm_exports.cpp exposes EMSCRIPTEN_KEEPALIVE offset functions, and the Offsets proxy reads them at runtime from the WASM module — so a C struct layout change can't silently desync from the TS side.