Add SSE response schemas for streaming endpoints

[Copilot]

Streaming endpoints were returning empty text/event-stream content without proper schemas. This adds typed SSE event schemas following the Speakeasy SSE pattern.

Changes

• New StreamingSchemaGenerator - Creates event type schemas with discriminated unions:

  • 10 event types: update, delete, notification, filters_changed, conversation, announcement, announcement.reaction, announcement.delete, status.update, notifications_merged
  • Endpoint-specific schemas (e.g., StreamingUserEvent, StreamingDirectEvent) with only relevant event types
  • Payload types reference existing entities (Status, Notification, etc.) with oneOf for string/object flexibility

• Updated MethodConverter - Streaming endpoints now reference appropriate event schemas instead of empty content

Example

Before:

"text/event-stream": {}

After:

"text/event-stream": {
  "schema": { "$ref": "#/components/schemas/StreamingUserEvent" }
}

Where StreamingUserEvent is:

{
  "oneOf": [
    { "$ref": "#/components/schemas/UpdateEvent" },
    { "$ref": "#/components/schemas/DeleteEvent" },
    { "$ref": "#/components/schemas/NotificationEvent" },
    ...
  ]
}

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• otel.cloud.redocly.com
  • Triggering command: /opt/hostedtoolcache/node/24.11.1/x64/bin/node node /home/REDACTED/work/mastodon-openapi/mastodon-openapi/node_modules/.bin/redocly lint --format=github-actions dist/schema.json (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Stream response schemas</issue_title>
<issue_description>Add schema for the data shapes in the streaming endpoints.

• API docs: https://docs.joinmastodon.org/methods/streaming/
• Example SSE implementation in OpenAPI: https://www.speakeasy.com/docs/sdks/customize/runtime/server-sent-events

The content type should be updated to text/event-stream. Implement schemas similar to "Handling Multiple Event Types" from the example link.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Stream response schemas #166

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