Add connection management API endpoints and models

[jfrench9]

Summary

Introduces a complete connection management module to the robosystems_client, providing full CRUD operations and OAuth support for external data provider connections. This feature adds 8 new API endpoints and 20+ supporting model definitions, along with a minor update to the existing DownloadQuota model.

Key Accomplishments

New API Endpoints (api/connections/)

• Create Connection – Establish new connections to external providers
• Delete Connection – Remove existing connections
• Get Connection – Retrieve details for a specific connection
• Get Connection Options – Fetch available configuration options for providers
• List Connections – Query and filter all connections with provider type filtering
• Init OAuth – Initiate OAuth authentication flows with configurable additional params
• OAuth Callback – Handle OAuth redirect callbacks to complete authentication
• Sync Connection – Trigger data synchronization on a connection with customizable sync options

New Models

• Connection models: ConnectionResponse, ConnectionResponseMetadata, ConnectionOptionsResponse, ConnectionProviderInfo (with auth type and provider enums)
• Request models: CreateConnectionRequest, OAuthInitRequest, OAuthCallbackRequest, SyncConnectionRequest
• Response models: OAuthInitResponse, SyncConnectionResponseSyncconnection
• Provider-specific configs: PlaidConnectionConfig (with accounts and institution types), QuickBooksConnectionConfig, SecConnectionConfig
• Supporting types: ListConnectionsProviderType0, CreateConnectionRequestProvider, OAuthInitRequestAdditionalParamsType0, SyncConnectionRequestSyncOptionsType0

Modified Models

• DownloadQuota – Updated attribute definitions (28 lines changed, likely field type or naming adjustments)
• models/__init__.py – Updated to export all new model classes

Breaking Changes

• The DownloadQuota model has been modified. Consumers relying on its previous attribute structure should verify compatibility after upgrading.

Testing Notes

• Verify each of the 8 connection API endpoints for correct request serialization and response deserialization
• Test OAuth flow end-to-end (init → callback) to ensure proper state handling
• Validate provider-specific configurations (Plaid, QuickBooks, SEC) with realistic payloads
• Confirm DownloadQuota changes do not regress existing functionality that depends on this model
• Test list_connections filtering by provider type, including union/optional type handling

Infrastructure Considerations

• This is a client-side SDK change; no backend deployment is required, but the corresponding API endpoints must be available on the target environment
• New provider integrations (Plaid, QuickBooks, SEC) may require environment-specific credentials and OAuth redirect URI configuration
• The OAuth callback endpoint implies a redirect flow — ensure client applications have appropriate callback handling in place

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Branch Info:

• Source: feature/connection-management
• Target: main
• Type: feature

Co-Authored-By: Claude noreply@anthropic.com