Fix didPanic to use type assertion for runtime.PanicNilError instead of string comparison

[Copilot]

didPanic detects panic(nil) by comparing err.Error() == "panic called with nil argument". Go 1.27 changes this error string (golang/go#63813, CL 791540), breaking the check.

• Replace string equality check with a direct *runtime.PanicNilError type assertion, which is the stable API available since Go 1.21

// Before
if err, ok := message.(error); ok {
    if err.Error() == "panic called with nil argument" {
        message = nil
    }
}

// After
if _, ok := message.(*runtime.PanicNilError); ok {
    message = nil
}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.69%. Comparing base (a0b676d) to head (15fd903).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #124      +/-   ##
==========================================
+ Coverage   91.68%   91.69%   +0.01%     
==========================================
  Files          97       97              
  Lines       12602    12601       -1     
==========================================
+ Hits        11554    11555       +1     
+ Misses        826      825       -1     
+ Partials      222      221       -1     

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