[fix] reject configuration setters after execution instead of silently applying

[vt128]

Problem

Every configuration setter's godoc promised "It panics if called after execution." The implementation was:

if s.hasExec {
    log.DPanic("cannot ... after execution")
}
// ...falls through and applies the change anyway

Two defects compound:

1. Fall-through. Even when the guard fired, the setter kept going and mutated Box state — so a post-execution config change landed rather than being rejected.
2. Silent by default. The package logger defaults to zap.NewNop().Sugar(), whose DPanic neither panics nor logs. So with the default logger the guard was a complete no-op and the doc's contract was simply false.

Fix (fail-closed)

• New helper deniedAfterExec(action): logs the misuse through the package logger (which still panics under a development logger, preserving that behaviour) and returns true so the caller bails out without applying the change.
• All 26 guards converted 1:1 from if s.hasExec { log.DPanic(...) } to if s.deniedAfterExec("...") { return } (the 3 non-void setters EnableConsoleCapture / CreateMemory / AddHTTPContext return nil). No guard was missed; each still runs under s.mu.
• Docs updated on all setters: "Calling it after execution is rejected: the change is ignored, and it panics under a development logger." — now the code and the contract agree, both under the default (silent, ignore) and development (panic) loggers.

Test

TestSetterAfterExecIsFailClosed (test-first): with the default Nop logger, calling SetMaxOutputEntries after a run is silently ignored (no panic, no error) and a subsequent multi-entry run is unaffected — proving the mutation did not land. The existing development-logger panic table test continues to assert a panic per setter.

Verification

gofmt/go vet clean; go test, go test -race -count=2, and docker golang:1.19 go test -race all green.

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 6 complexity · -2 duplication

Metric	Results
Complexity	6
Duplication	-2

View in Codacy

🟢 Coverage 100.00% diff coverage · +0.00% coverage variation

Metric	Results
Coverage variation	✅ +0.00% coverage variation (-1.00%)
Diff coverage	✅ 100.00% diff coverage

View coverage diff in Codacy

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (b90ec7d)	1169	1160	99.23%
Head commit (a8b7c67)	1175 (+6)	1166 (+6)	99.23% (+0.00%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#30)	58	58	100.00%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.97%. Comparing base (b90ec7d) to head (a8b7c67).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #30   +/-   ##
=======================================
  Coverage   98.96%   98.97%           
=======================================
  Files          12       12           
  Lines         871      876    +5     
=======================================
+ Hits          862      867    +5     
  Misses          5        5           
  Partials        4        4           

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