* fix(modules): allow disabling logging and configuring optional fields in LB backend services
Replaced 'log_sample_rate' (number) with 'log_config' (object) in all Load Balancer Backend Service modules. This allows explicitly disabling logging ('enable = false') and configuring advanced options like 'optional_mode' and 'optional_fields', resolving infinite plan drift and the inability to disable logging.
Affected modules:
- net-lb-app-ext-regional
- net-lb-app-ext
- net-lb-app-int-cross-region
- net-lb-app-int
- net-lb-ext
- net-lb-int
- net-lb-proxy-int
Added test cases and updated documentation.
Fixes#3914
* style: format variables files with terraform fmt
* docs: add critical linting rule for AI agents to GEMINI.md
bf9ccb7547