Add BetterTogether::Seed

[rsmithlal]

Summary of Changes

This pull request introduces BetterTogether::Seed, a new interoperable data protocol for the Community Engine platform. The Seed facilitates structured import/export of data, supporting:

• Platform migrations (moving data between platforms)
• Data backups and restores
• Inter-platform data sharing over the internet (enabling federated platforms to exchange information in a controlled way)

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Key Features & Changes

1. New BetterTogether::Seed Model

• Central record for tracking a unit of exported or imported data.
• Stores structured data (payload) and metadata (origin), including:
  • Contributors
  • Platform version
  • License
  • Usage notes
• Supports attachment of a YAML file via Active Storage to allow easy download, transfer, or archival.

2. Seedable Concern for Models

• Adds a Seedable module that any model can include to become seed-exportable.
• Implements #plant, #export_as_seed, and #export_as_seed_yaml.
• Supports exporting single records or collections.
• Models currently made seedable:
  • Person
  • Wizard
  • WizardStep
  • WizardStepDefinition

3. SeedsController for CRUD UI

• Basic admin UI to view, create, and manage seeds.
• Accessible via /seeds in the admin panel.

4. Import/Export Workflow

• Seeds can be created directly from records (manual export).
• Seeds can also be loaded from files (manual import).
• Supports two approaches to import:
  • Direct file path.
  • Predefined namespace lookup (config/seeds/...).

5. Schema Migration

• New table better_together_seeds with:
  • Polymorphic seedable association.
  • origin and payload JSONB columns (indexed for performance).
  • Index on type + identifier for fast lookup.

6. FactoryBot Factories & Shared Example

• Adds factories for seeds.
• Introduces a shared_examples file to ensure any seedable model behaves correctly.

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Why This Matters

The Seed is a foundational piece of Community Engine’s commitment to data sovereignty. By enabling structured data import/export in a standard format, it:

✅ Empowers communities to migrate between platforms with minimal friction.
✅ Enables true data ownership, giving admins the ability to back up and restore their data anytime.
✅ Sets the groundwork for future federated platform collaboration, where platforms can exchange content in a structured, permissioned way.

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Testing & Coverage

• Includes full RSpec test suite for:
  • Seed model.
  • Seedable concern.
  • Controller CRUD actions.
  • View rendering for seeds.
• Adds a shared example ensuring all future seedable models adhere to the expected interface.

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Files Changed

• 32 files changed
• 1,038 additions / 83 deletions

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Migration Required

✅ Yes – create_better_together_seeds

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Related Issues

• Lays the groundwork for federated data exchange across platforms.
• Supports backup/restore requirements for local hosting scenarios.

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Suggested Next Steps

• Document the Seed structure and format for third-party implementers.
• Add support for bulk import/export from the command line.
• Implement integration test cases for end-to-end import/export cycles across multiple platforms.