[Junie]: Integrate Shopee Brand Portal Performance APIs

[github-actions]

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• 🔗 Issue: Fixes: [Important] Brand Portal Service OpenAPI Now Available [Shopee-ID:1462] #32

📊 Junie Summary:

Summary

• Added support for Shopee Brand Portal OpenAPI announcement #1462 by introducing all newly announced v2.principal.* performance endpoints in the SDK.
• Extended client auth/signature flow to support principal_id-scoped calls while keeping existing shop_id behavior intact.

Changes

• Added new resource src/Resources/Principal.php with 11 endpoint wrappers for sales, affiliate, livestream, and video performance APIs.
• Updated src/Client.php to register/read Principal resource, add setPrincipalAccessToken($principal_id, $access_token), inject principal_id into signed requests, and sign using principal_id when present.
• Added/updated tests: new tests/Resources/PrincipalTest.php for all 11 endpoint mappings, plus tests/ClientTest.php coverage for Principal resource access and principal-vs-shop signature behavior.

Verification

• Ran full test suite with composer test.
• Result: OK (273 tests, 531 assertions).

[nVuln]

@junie-agent rename resource class Principal to BrandPortal

[github-actions]

Junie successfully finished!

Rename Principal resource class to BrandPortal

Summary

• Renamed the Shopee performance resource from Principal to BrandPortal across implementation and tests, as requested.
• Kept all endpoint paths and behavior intact (still mapped to v2.principal.* routes).

Changes

• Renamed src/Resources/Principal.php → src/Resources/BrandPortal.php and updated class name to BrandPortal.
• Updated src/Client.php to import/register BrandPortal and expose it via @property-read BrandPortal $BrandPortal.
• Renamed tests/Resources/PrincipalTest.php → tests/Resources/BrandPortalTest.php and updated test class/imports/fixtures accordingly.
• Updated tests/ClientTest.php resource access test to use $client->BrandPortal and BrandPortal::class.

Verification

• Ran full test suite with composer test after installing dependencies; result: OK (273 tests, 531 assertions). Commit sha: a5b1641