fix(ci): resolve go vet redeclaration in session continue-stream tests

[Copilot]

Description

The Format, vet, test, and build workflow failed because go vet detected a duplicate test type declaration in internal/handler/session. This PR removes the collision with a minimal, test-only rename.

• Root cause

  • stubSessionService in continue_stream_resource_urls_test.go conflicted within the session test package during vet analysis.

• Change

  • Renamed the local test stub type and receiver to a file-specific name and updated its construction site.

type stubContinueStreamSessionService struct {
	interfaces.SessionService
}

func (s *stubContinueStreamSessionService) GetSession(_ context.Context, id string) (*types.Session, error) {
	return &types.Session{ID: id, TenantID: 1}, nil
}

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 💥 Breaking change
• 📚 Documentation update
• 🎨 Refactor
• ⚡ Performance improvement
• 🧪 Test
• 🔧 Configuration / Build / CI

Related Issue

Handled by automatic issue linking.

Testing

Confirmed the prior vet failure condition is removed and package-level continue-stream tests still pass.

Checklist

• git diff --check origin/main...HEAD passes
• Changed source files are formatted
• Targeted tests for the changed packages/components pass
• Diff-scoped lint passes where applicable (for Go: golangci-lint run --new-from-rev=origin/main ./...)
• Full-repository checks were run, or any unrelated/environment-dependent failures are documented above
• Self-reviewed the code
• Added/updated tests covering the change
• Updated related documentation (README, docs/, Swagger annotations, etc.)
• Breaking changes are clearly called out in the description above

Screenshots / Recordings

N/A (no user-visible UI change)