fix: prevent shared Option causing race by switching to value instead of pointer

[ngocphuongnb]

Pool creation used *Option, causing all runtimes to share the same Option.ProxyFunction. ProxyFunction is created using the runtime-specific registry:

if option.ProxyFunction == nil {
    option.ProxyFunction = createFuncProxyWithRegistry(registry)
}

As a result:

• All runtimes reused the same ProxyFunction.
• JS functions failed to call properly because the Go function was registered in a different runtime’s proxyRegistry.

Fix:
Replace *Option with Option (value type) to ensure each runtime gets its own ProxyFunction bound to the correct registry.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.74%. Comparing base (d34497f) to head (903b8b5).
⚠️ Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #21      +/-   ##
==========================================
- Coverage   99.74%   99.74%   -0.01%     
==========================================
  Files          15       15              
  Lines        3579     3576       -3     
==========================================
- Hits         3570     3567       -3     
  Misses          5        5              
  Partials        4        4              

Files with missing lines	Coverage Δ
options.go	100.00% <100.00%> (ø)
proxy.go	100.00% <ø> (ø)
runtime.go	98.78% <100.00%> (-0.01%)	⬇️

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