Recycle retained WASM workers after memory high-water

[wolfy-j]

Summary

• recycle a single warm WASM worker after a completed call when retained linear memory exceeds limits.max_retained_memory_bytes
• use isolated component module/runtime ownership for replacement so WASI component bridges do not corrupt reused modules
• use binary-string list<u8> decode globally for Wippy-managed WASM results, avoiding the extra Go []byte -> Lua string copy without adding app-level flags
• reduce Lua fs.readfile churn by avoiding bytes.Buffer.String and cover binary readback

Dependency

• depends on Support binary string byte-list results wasm-runtime#5 for InstantiateWithConfig and binary-string byte-list decode support
• pinned to github.com/wippyai/wasm-runtime v0.0.0-20260621204001-8eab7f42df1b

Validation

• make lint
• go test ./api/runtime/wasm ./runtime/wasm/engine ./runtime/wasm/component/function ./runtime/wasm/component/process ./runtime/lua/modules/fs ./system/scheduler/pool/adaptive ./system/scheduler/pool/inline ./system/scheduler/pool/lazy ./system/scheduler/pool/static -count=1
• make build-wippy-linux-amd64