[SDK: Python] Add Webhook endpoints/interface

[infinityplusone]

Changes

Adds comprehensive Webhooks v2 client support and multiple new API endpoints to the tango-python SDK.

Webhooks v2 Support

• Event type discovery: list_webhook_event_types() to discover supported event types and subject types
• Subscription management: Full CRUD operations for webhook subscriptions
  • list_webhook_subscriptions() - List subscriptions with tier-capped pagination (page + page_size)
  • get_webhook_subscription() - Get a single subscription by ID
  • create_webhook_subscription() - Create a new subscription
  • update_webhook_subscription() - Update subscription name and/or payload
  • delete_webhook_subscription() - Delete a subscription
• Endpoint management: Full CRUD operations for webhook endpoints
  • list_webhook_endpoints() - List endpoints with standard pagination
  • get_webhook_endpoint() - Get a single endpoint by ID
  • create_webhook_endpoint() - Create a new endpoint (one per user)
  • update_webhook_endpoint() - Update endpoint callback URL and/or active status
  • delete_webhook_endpoint() - Delete an endpoint
• Testing utilities:
  • test_webhook_delivery() - Send a test webhook to verify endpoint connectivity
  • get_webhook_sample_payload() - Fetch sample payloads for development/testing
• Type definitions: Complete dataclasses for all webhook models (WebhookSubscription, WebhookEndpoint, WebhookEventType, etc.)

New API Endpoints

• Offices: list_offices(), get_office() - Office hierarchy data
• Organizations: list_organizations(), get_organization() - Organization structure with response shaping
• OTAs: list_otas(), get_ota() - Other Transaction Agreements
• OTIDVs: list_otidvs(), get_otidv() - Other Transaction IDVs
• Subawards: list_subawards() - Subaward data with response shaping
• NAICS: list_naics() - NAICS code lookup
• Assistance: list_assistance() - Federal assistance awards

Other Changes

• HTTP client: Added _patch() and _delete() helper methods for webhook management endpoints
• Search support: Added search parameter to list_agencies()
• New model schemas: Organization, OTA, OTIDV, Subaward
• Default shapes: Shape configurations for all new endpoints
• Explicit schemas: Response shaping support for new endpoints

Why

This implements:

1. The full Webhooks v2 API surface area from the Tango server, enabling SDK users to discover event types, manage subscriptions/endpoints, and test webhook delivery
2. Coverage for additional Tango API endpoints (Offices, Organizations, OTAs, OTIDVs, Subawards, NAICS, Assistance)

Testing

• Comprehensive test suite covering all webhook endpoints
• Integration tests with VCR cassettes for new endpoints
• Production smoke tests for all new functionality
• New check_filter_shape_conformance.py script for validating filter/shape support

Documentation

• Updated API reference with all new endpoints
• Updated developer guide with new endpoint examples
• Updated SHAPES.md with new shape configurations

Notes

• Pagination: Subscriptions use page + page_size (tier-capped), while endpoints use page + limit
• Tier gating: "Catch-all" subscriptions (empty subject_ids) require Enterprise tier
• Deliveries/redelivery: The server API does not currently expose public endpoints for listing deliveries or redelivery operations
• Signature verification: Documentation includes Python code snippet for verifying webhook signatures (HMAC-SHA256)

Related

Resolves makegov/tango#1274