Some CONFIG_OVERWRITE_JSON system parameters are missing from the documentation

Hello,

The official Harbor documentation for configuring system settings via the CONFIG_OVERWRITE_JSON environment variable is incomplete.
Several system configuration keys are available through the API but are not documented for CONFIG_OVERWRITE_JSON.

While inspecting /api/v2.0/configurations and testing CONFIG_OVERWRITE_JSON in Harbor 2.14.0, I confirmed that the following keys work correctly, but are missing from the documentation: [https://goharbor.io/docs/2.14.0/install-config/configure-system-settings-cli/#harbor-configuration-items](https://goharbor.io/docs/2.14.0/install-config/configure-system-settings-cli/#harbor-configuration-items)
`notification_enable`
`quota_per_project_enable`
`storage_per_project`
`session_timeout`
`disabled_audit_log_event_types`

These settings are not listed in the “Configuration Items” section of the documentation.
Quota-related fields are especially important, as they allow configuring the default project quota, but admins currently have no way to discover them unless inspecting the API (or web interface).
This creates an inconsistency between Harbor’s documented configuration capabilities and its actual behavior.

Environment:
- Harbor version: 2.14.0
- Installation type: docker-compose
- Behavior reproduced consistently

Thanks for your work, I would like improve this documentation would make Harbor significantly easier to configure declaratively and automate in IaC workflows.

Start with the “Configuration Items” section at install-config/configure-system-settings-cli/#harbor-configuration-items in the Harbor documentation. Add notification_enable, quota_per_project_enable, storage_per_project, session_timeout, and disabled_audit_log_event_types, then verify that all five settings are listed consistently with the existing entries.

Written by the indexing model from the issue text.