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.

⚠️ 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.
• PUT /api/v1/workflow/contentlet/actions/bulk/fire and POST /api/v1/workflow/contentlet/actions/_bulkfire behave identically; _bulkfire streams via SSE.
• For batches larger than a few contentlets, the synchronous response can exceed common client timeouts (e.g. ~15 s for the MCP sandbox). The server-side work typically completes; verify with _search.