[Petebro-MSFT (Petebro-MSFT)]

Supersedes #233 and incorporates #215. Thanks Cláudio Silva (@ClaudioESSilva) and bdevries (@Branden-DeVries); both are credited as co-authors.

Changes

• Write-RsCatalogItem uploads .gif, .bmp, .pdf, .xls and .xlsx as resources with explicit MIME types.
• Write-RsFolderContent uploads .gif, .bmp and .pdf. It still skips Excel files, because the default server upload allowlist rejects .xls/.xlsx and failing a whole folder upload would be a regression.
• Fixes from Support gif, bmp, xls, xlsx and pdf @ Write-RSFolderContent & Write-RsCatalogItem #233: .xls uses application/vnd.ms-excel (not the XLSX type), .jpg stays image/jpeg, and the resource error message is kept.
• appveyor.yml adds *.xls to AllowedResourceExtensionsForUpload (this caused the Support gif, bmp, xls, xlsx and pdf @ Write-RSFolderContent & Write-RsCatalogItem #233 CI failure).
• Tests: integration contexts for both commands (test files are generated at runtime; no new binaries), plus offline unit tests in Tests/Unit/CatalogItemResourceUpload.Tests.ps1.

Notes

• PBIRS stores .pdf resources as application/octet-stream regardless of the MIME type sent, so the PDF test accepts either value.
• .xlsm is not included; it could be a follow-up.

Validation

• Unit tests: 45/45 pass (Windows PowerShell 5.1, Pester 4.10.1). The new unit file fails 8 of 14 on master and passes 14/14 here.
• Local PBIRS: new integration contexts pass (5/5, Excel cases excluded because of the default allowlist); gif/bmp stored as image/gif/image/bmp; folder upload skips xlsx.
• PSScriptAnalyzer: no new warnings.