fix(module): prevent double-free when initializing native module exports

[buke]

QuickJS JS_SetModuleExport takes ownership of the JSValue passed in. We were passing Go-owned values directly, which could later be freed again on the Go side, leading to intermittent ref_count assertion failures during JS_FreeRuntime (issue #688).

After handing an export value to JS_SetModuleExport, invalidate the Go Value so subsequent Free() becomes a no-op. Also release the duplicated module private value and propagate export init failures.

Add a regression stress test that runs the minimal repro scenario 50 times.

[gemini-code-assist]

Summary of Changes

Hello @buke, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical memory management bug where native module exports could lead to double-free errors and runtime crashes in QuickJS. The changes ensure proper ownership transfer of JavaScript values between Go and QuickJS, preventing resource mismanagement, and include a robust regression test to safeguard against future recurrences of this issue.

Highlights

• Double-Free Prevention: Modified the handling of JS_SetModuleExport to prevent double-free issues (issue Module builder sometime have reference counting issue #688) by invalidating Go-owned JSValue references after ownership is transferred to QuickJS.
• Error Propagation: Ensured that module export initialization failures are properly propagated by returning an error code from the goModuleInitProxy function.
• Resource Management: Added explicit freeing of the module's private value (privateValue) to prevent potential resource leaks.
• Regression Test: Introduced a new stress test (TestModuleBuilder_RuntimeClosePanic_Minimal) that runs the minimal reproduction scenario 50 times to verify the fix for runtime panics during module cleanup.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (1e076ef) to head (df4f908).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #689   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           11        11           
  Lines         2343      2349    +6     
=========================================
+ Hits          2343      2349    +6     

Files with missing lines	Coverage Δ
bridge.go	100.00% <100.00%> (ø)

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[gemini-code-assist]

Code Review

This pull request correctly addresses a double-free vulnerability by invalidating the Go-side Value after its ownership is transferred to QuickJS's JS_SetModuleExport. The changes also improve error propagation and add a valuable regression stress test to prevent this issue from recurring. My review includes one critical suggestion to prevent a resource leak on the error path within the module initialization proxy.