Feature: import and export controls via JSON files

[lan17]

Summary

• Add support for exporting controls to a JSON file and importing controls from a JSON file.
• Export should support either all controls or a selected subset.
• Import should load controls from JSON, validate them, and persist them in the database.

Motivation

• Makes it easy to share reusable control bundles across users and environments.
• Enables publishing JSON files for common policies / recommended control sets.
• Provides a straightforward backup and migration path for control definitions.

Current behavior

• Controls can be created, copied, edited, and stored in the database, but there is no import/export flow for sharing or reusing them as files.
• The UI has a Control Store and per-control editing/copy flows, and the server has control CRUD plus validation endpoints, but nothing supports bulk JSON import/export.

Expected behavior

• Users can click Export to download either all controls or a selected subset as a JSON file.
• Users can click Import to upload a JSON file, validate its contents, and store the imported controls in the database.
• The exported format is shareable so common policies/control bundles can be published and reused.

Reproduction (if bug)

1. Open the control management / Control Store UI.
2. Try to share, back up, or move a set of controls between environments.
3. There is no import/export workflow today.

Proposed solution (optional)

• Add an export action in the Control Store that serializes either all controls or a user-selected subset to a versioned JSON payload.
• Add an import flow that parses uploaded JSON, validates each control using existing control-definition and evaluator validation, and persists valid controls.
• Surface conflicts and invalid entries during import instead of failing silently.
• Decide import conflict behavior explicitly (for example: skip existing names, overwrite, or import with rename).
• Decide whether v1 should cover only control definitions or also policy associations.

Additional context

• This feature lines up with the existing UI Control Store and control CRUD / validation APIs.
• Open questions to resolve during implementation:
  • JSON schema/versioning for forward compatibility
  • Whether import/export should include policy membership or remain controls-only in v1
  • UX for duplicate names and partial import failures