Implement proper OAuth2 refresh token flow

[augard]

Summary

• Implements standard OAuth2 refresh token flow for better token management
• Adds fallback to credential-based login when refresh token fails
• Updates ApiRequest protocol to support authorization header control

Changes

• ✨ Added dedicated refreshToken() method in Api class for OAuth2 refresh token grant type
• 🔄 Updated refreshTokenIfPossible() to attempt refresh token flow before credential fallback
• 🛠️ Modified TokenResponse model to make refresh token optional (needed for refresh responses)
• 🔧 Enhanced ApiRequest protocol with authorization parameter to control header inclusion
• ✅ Updated test implementations to match the new ApiRequest protocol

Implementation Details

The token refresh now follows OAuth2 best practices with this priority:

1. Primary: Use refresh_token grant type if a refresh token is available
2. Fallback: Use stored credentials for full re-authentication if refresh fails
3. Preservation: Device ID and stamp are maintained during token refresh

Test Plan

• Verify refresh token flow works when token expires
• Confirm fallback to credential login when refresh fails
• Ensure device ID and stamp are preserved
• Test that authorization headers are properly controlled
• Verify all existing tests pass with updated ApiRequest protocol

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR implements proper OAuth2 refresh token flow for better token management and adds fallback to credential-based login when refresh token fails.

Key changes:

• Added dedicated OAuth2 refresh token flow with fallback to credential-based authentication
• Enhanced ApiRequest protocol to support authorization header control
• Updated TokenResponse model to make refresh token optional for refresh responses

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
KiaMaps/Core/Api/Api.swift	Added new refreshToken() method for OAuth2 refresh token grant type
KiaMaps/App/ApiExtensions.swift	Updated token refresh logic to try refresh token first, then fallback to credentials
KiaMaps/Core/Api/Models/AuthenticationModels.swift	Made refresh token optional in TokenResponse model
KiaMaps/Core/Api/ApiRequest.swift	Enhanced protocol and implementation with authorization parameter
KiaTests/AuthenticationTests.swift	Updated mock implementation to match new ApiRequest protocol
KiaTests/UIComponentMockDataTests.swift	Fixed parameter name casing in test calls

Comments suppressed due to low confidence (1)

KiaMaps/Core/Api/Models/AuthenticationModels.swift:1

• Using an empty string as fallback for missing refresh token could cause issues. Consider handling the nil case explicitly or documenting why an empty string is appropriate here.

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