feat(ai): add AI Gateway support

[innomaxx]

Closes #248

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.35%. Comparing base (f3bca05) to head (f20705c).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #271      +/-   ##
============================================
+ Coverage     93.30%   93.35%   +0.05%     
- Complexity     1840     1850      +10     
============================================
  Files           169      171       +2     
  Lines          4969     5005      +36     
============================================
+ Hits           4636     4672      +36     
  Misses          333      333              

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[Copilot]

Pull request overview

Adds SDK support for the Crowdin AI Gateway endpoints (per #248), enabling consumers of this PHP client to proxy GET/POST/PUT/PATCH/DELETE requests through Crowdin’s AI Gateway for both Crowdin and Enterprise environments.

Changes:

• Introduces AiGatewayApi (Crowdin) and Enterprise\AiGatewayApi with gateway GET/POST/PUT/PATCH/DELETE methods.
• Adds a generic AiGatewayResponse model to wrap the API’s data payload.
• Registers the new aiGateway service on the Crowdin client and adds unit tests for both environments.

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
src/CrowdinApiClient/Api/AiGatewayApi.php	Adds Crowdin (non-Enterprise) AI Gateway API methods under /users/{userId}/ai/providers/{providerId}/gateway/{path}.
src/CrowdinApiClient/Api/Enterprise/AiGatewayApi.php	Adds Enterprise AI Gateway API methods under /ai/providers/{providerId}/gateway/{path}.
src/CrowdinApiClient/Model/AiGatewayResponse.php	Adds a lightweight response model for AI Gateway responses.
src/CrowdinApiClient/Crowdin.php	Exposes the new $aiGateway API service in both standard and Enterprise service lists.
tests/CrowdinApiClient/Api/AiGatewayApiTest.php	Adds unit tests covering Crowdin AI Gateway GET/POST/PUT/PATCH/DELETE behavior.
tests/CrowdinApiClient/Api/Enterprise/AiGatewayApiTest.php	Adds unit tests covering Enterprise AI Gateway GET/POST/PUT/PATCH/DELETE behavior.

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