Create a companies watcher agent

Creates a Companies watcher (from a list) agent (companies-watcher). Watches the COMPANIES of an existing list (exactly one of listId/listIds) for the chosen eventType; job-posting watchers require at least one keywords entry and accept jobPostingLocationTypes (remote/on_site/hybrid). company-watch-new-hires watches the companies but collects the PEOPLE they hire: its results list is a contact list, and it requires signalFilters.titleKeywords. With start: false (the default) a DRAFT is saved — status initializing, nothing billed: read it back with GET /business/agents/{agentId}, adjust it with PATCH /business/agents/{agentId}, then start it with POST /business/agents/{agentId}/activate. With start: true the agent is created AND started in one call: its dedicated results list is created, credits are checked and spent, and the provider subscriptions are set up. Either way the answer is 201 { agent: { id, type, name, status, started } } — the same shape for every agent kind, draft or started. Poll GET /business/agents for status and contactsFound, and read the delivered rows with the Lists endpoints via the agent's listId. Free-plan accounts hold at most 10 agents, drafts included (403 AGENT_LIMIT_REACHED). Every field below is validated by the agents service: a rejected field answers 422 VALIDATION_FAILED, naming it in param and describing every failure in message. listName must not collide with an existing list or agent name (409 LIST_NAME_TAKEN), and starting without enough credits answers 402 INSUFFICIENT_CREDITS without creating anything.

Errors:

• 422 VALIDATION_FAILED — The request was rejected by validation. Either this endpoint's own request validation (a malformed body), or the agent config itself: a field missing, out of range or not one of the accepted values, or a business rule broken (an expirationDate that is not in the future, more industries than the kind accepts, a notification count out of range). param names the first offending field and message lists every failure.
• 409 LIST_NAME_TAKEN — listName is already used by one of your lists or agents. Pick another name.
• 402 INSUFFICIENT_CREDITS — The workspace does not have enough credits to start this agent. Nothing was created or spent.
• 403 AGENT_LIMIT_REACHED — Free-plan accounts may hold at most 10 agents, drafts included. Delete an agent or upgrade the plan.
• 404 LIST_NOT_FOUND — A source list named in listId / listIds does not exist or does not belong to the token owner.
• 422 AGENT_SOURCE_LIST_EMPTY — The source list holds nothing this agent kind can watch — no LinkedIn URLs, no companies, or no trackable contacts. Fill the list first.
• 400 INVALID_REQUEST — The agents service rejected the request for a reason this API does not model specifically. The request is not retryable unchanged.
• 429 RATE_LIMITED — The agents bucket is exhausted: 30 requests per minute or 2,000 per day per token owner, shared by every /business/agents operation (a 429 raised by the agents service is relayed with this code too). Retry after the Retry-After header.
• 500 UNEXPECTED_ERROR — The agents service failed (5xx, refused service credential, or a timeout after 60s) or the rate limiter was unavailable. Retry later; quote request_id to support.

Requires one of the following token scopes: agents.