chore: Migrate testing infrastructure to WireMock Docker Compose

[fern-api]

🔧 Changes

This PR updates the testing infrastructure and SDK code. Key changes include:

Testing Infrastructure Overhaul

• Replaced testcontainers with WireMock Docker Compose: Migrated from testcontainers to a simpler WireMock docker-compose setup for testing
• Added wiremock/docker-compose.test.yml: New docker-compose configuration for WireMock
• Added wiremock/wiremock-mappings.json: WireMock stub mappings for API mocking
• Updated Makefile: Test targets now automatically start/stop WireMock container

Dependency Cleanup

• Removed wiremock testcontainers dependencies
• Removed all transitive dependencies related to testcontainers (Docker, OpenTelemetry, etc.)
• Significantly reduced go.sum file size

Test Code Refactoring

• Simplified all WireMock test files to use direct HTTP calls to WireMock admin API
• Removed TestMain setup functions that initialized testcontainers
• Added ResetWireMockRequests and VerifyRequestCount helper functions
• Tests now connect to http://localhost:8080 (WireMock default)

SDK Code Changes

• Updated Page type signature to include Response in generic parameters: core.Page[*Cursor, *Item, *Response]
• Updated PageRequest and PageResponse to use core package types
• All paginated methods now expose the full response object

📚 References

• Auto-generated from latest Auth0 API definition

🔬 Testing

• Tests use WireMock for HTTP mocking
• Run make test to execute tests (automatically starts WireMock container)
• WireMock container is automatically cleaned up after tests

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 99.11111% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 22.80%. Comparing base (3d07f43) to head (ae7fdfb).

Files with missing lines	Patch %	Lines
management/internal/pager.go	88.88%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #661      +/-   ##
==========================================
+ Coverage   22.78%   22.80%   +0.02%     
==========================================
  Files         302      302              
  Lines      110013   110183     +170     
==========================================
+ Hits        25067    25128      +61     
- Misses      83100    83211     +111     
+ Partials     1846     1844       -2     

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