Harden FixCalcs package dependencies and API

[jochenwezel]

Summary

• remove the unused Microsoft.Extensions.Configuration.Json dependency path and replace the unused cryptography XML package with the required PKCS dependency
• add netstandard2.0 and net8.0 assets while retaining net48 and net6.0
• make XlsEpplusFixCalcsEdition sealed/static-only, add the three missing HttpListenerContext export overloads, and fix the remaining one-based worksheet lookup
• preserve the stricter table/worksheet validation and add API, stream-export, validation, and worksheet-index regression tests
• synchronize the generated XlsEpplusPolyformEdition API and update the copy script for the sealed class declaration
• remove stale configuration samples because worksheet indexing is initialized to zero-based and can only be changed programmatically

Compatibility notes

• WriteDataTableToXlsStream is now Shared/static. This is intentionally source- and binary-breaking for callers that invoked it through an instance.
• XlsEpplusFixCalcsEdition and the synchronized XlsEpplusPolyformEdition are now NotInheritable/sealed by explicit product decision.
• The netstandard2.0 build omits the legacy AllowPartiallyTrustedCallers attribute so .NET Framework 4.7.2 consumers can use CodePagesEncodingProvider without a MethodAccessException.

Verification

• The full CI_CD solution build succeeds after running clone-build-files.ps1.
• Release builds succeed for net48, netstandard2.0, net6.0, and net8.0.
• NuGet vulnerability audits report no vulnerable direct or transitive packages for either FixCalcs project.
• Full net8.0 test suite: 246 passed, 15 skipped, 0 failed.
• Focused FixCalcs and Polyform tests: 8 passed on net48 and 8 passed on net8.0.
• A net472 consumer smoke test successfully creates a workbook through the new netstandard2.0 asset.
• API documentation check and git diff check pass.
• Release packages contain all four target-framework assets and no Newtonsoft.Json, Configuration.Json, or Security.Cryptography.Xml dependency.

Release

Do not publish from this branch. Merge after review and successful pull-request checks, wait for the successful post-merge main build, and only then create the release.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.MsExcelComInteropTest.dll

2 tests  ±0   2 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.Excel.Test.dll

55 tests  +4   55 ✅ +4   2s ⏱️ ±0s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.Excel.TestFreeSpireXls.dll

6 tests  ±0   6 ✅ ±0   1s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.MsExcelComInteropTest.dll

2 tests  ±0   2 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.Excel.Test.dll

55 tests  +4   55 ✅ +4   2s ⏱️ ±0s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.Excel.TestSpireXls.dll

6 tests  ±0   6 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.Excel.TestFreeSpireXls.dll

6 tests  ±0   6 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.Excel.TestSpireXls.dll

6 tests  ±0   6 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.MsExcelComInteropTest.dll

2 tests  ±0   2 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.Excel.Test.dll

263 tests  +4   263 ✅ +4   50s ⏱️ +12s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.Excel.TestFreeSpireXls.dll

75 tests  ±0   75 ✅ ±0   27s ⏱️ +7s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.Excel.TestSpireXls.dll

77 tests  ±0   77 ✅ ±0   18s ⏱️ -4s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 990f24c. ± Comparison against base commit a47853e.

♻️ This comment has been updated with latest results.