feat!: change default uploadFormat to 'raw'

[Artur-]

Switch the default upload format from 'multipart' to 'raw' binary uploads.

BREAKING CHANGE: The default upload format has changed from 'multipart' to 'raw'.
Existing applications that rely on multipart/form-data uploads must now explicitly
set upload-format="multipart" to maintain the previous behavior.

Changes:

• Change uploadFormat default value from 'multipart' to 'raw'
• Update documentation to reflect new default
• Fix existing tests to explicitly use 'multipart' where needed
• Update test names to clearly indicate which format they test

Migration guide:

• If your backend expects multipart/form-data, add upload-format="multipart":
  
• If your backend accepts raw binary (recommended), no changes needed

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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