feat: Add github_organization_security_configuration and github_enterprise_security_configuration resources

Adds two new resources to manage Code Security Configurations:

- github_organization_security_configuration: manages code security
  configurations at the organization level
- github_enterprise_security_configuration: manages code security
  configurations at the enterprise level

Both resources include:
- Full CRUD operations using GitHub's Code Security Configurations API
- Composite IDs (org/enterprise + config ID)
- 404-tolerant delete
- tflog structured logging throughout
- All optional fields use GetOk to avoid sending unset values
- Custom import support
- Shared expandCodeSecurityConfigurationCommon helper to avoid duplication
- All 4 delegated fields on enterprise: code_scanning_delegated_alert_dismissal,
  secret_scanning_delegated_bypass, secret_scanning_delegated_bypass_options,
  secret_scanning_delegated_alert_dismissal
- Fix flattenCodeScanningDefaultSetupOptions runner_type empty string drift

Acceptance tests (5 per resource):
- creates without error (with import verification)
- updates without error
- creates with nested options (runner, autosubmit)
- creates with minimal config (with import verification)
- creates with delegated bypass options

Documentation added for both resources.

Resolves integrations#2412

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sprioriello

github/provider.go

@@ -180,6 +180,7 @@ func Provider() *schema.Provider {
 			"github_organization_role_user":                                         resourceGithubOrganizationRoleUser(),
 			"github_organization_role_team_assignment":                              resourceGithubOrganizationRoleTeamAssignment(),
 			"github_organization_ruleset":                                           resourceGithubOrganizationRuleset(),
+			"github_organization_security_configuration":                            resourceGithubOrganizationSecurityConfiguration(),
 			"github_organization_security_manager":                                  resourceGithubOrganizationSecurityManager(),
 			"github_organization_settings":                                          resourceGithubOrganizationSettings(),
 			"github_organization_webhook":                                           resourceGithubOrganizationWebhook(),
@@ -217,6 +218,7 @@ func Provider() *schema.Provider {
 			"github_enterprise_actions_workflow_permissions":                        resourceGithubEnterpriseActionsWorkflowPermissions(),
 			"github_actions_organization_workflow_permissions":                      resourceGithubActionsOrganizationWorkflowPermissions(),
 			"github_enterprise_security_analysis_settings":                          resourceGithubEnterpriseSecurityAnalysisSettings(),
+			"github_enterprise_security_configuration":                              resourceGithubEnterpriseSecurityConfiguration(),
 			"github_workflow_repository_permissions":                                resourceGithubWorkflowRepositoryPermissions(),
 		},