Perform workflow actions on bulk content

This operation allows you to specify a multiple content items (either by query or a list of identifiers), a workflow action to perform on them, and additional parameters as needed by the selected action. Responses are streamed as Server-Sent Events.

⚠️ Important contract notes:

• contentletIds despite its name expects inodes, not identifiers. Passing identifiers results in a silent no-op with no error.
• additionalParams must be present, even when empty ({}). Omitting it returns a 500 NPE.
• The endpoint is not step-aware: if the action is not valid in a contentlet's current step, the input is dropped silently (no fails[] entry). Verify post-fire state via POST /api/content/_search.
• This endpoint behaves identically to PUT /api/v1/workflow/contentlet/actions/bulk/fire; only the response transport differs (SSE here vs JSON there).