Always remove all Bun-specific code and build targets

Always remove all Bun-specific code: delete dist/bun directories, replace Bun APIs (Bun.mmap, Bun.file, Bun.zstdDecompressSync, DecompressionStream('zstd'), @sentry/bun) with Node.js equivalents, remove Bun-specific mocks/test assertions/build targets. Enforce Node.js >= 22.15 + pnpm + Vitest stack. Use node:worker_threads, node:fs, node:zlib, node:https, vitest run, npx tsx. Bun bugs (#18145, #25677, #31158) cause model-init OOM in WASM paths — numThreads=1 avoids pthread paths. Load workers via new URL('./worker.ts', import.meta.url); use Float32Array structured clone; worker.unref() for clean exit. Never add new Bun-specific code.