feat: expand outreach targeting and messaging

docs/api.md

@@ -59,6 +59,7 @@ an administrator credential.
 | `GET` | `/api/v1/jobs` | List recent asynchronous jobs | read | no |
 | `GET` | `/api/v1/jobs/{id}` | Get asynchronous job state | read | no |
 | `POST` | `/api/v1/jobs` | Start chat or media synchronisation | control | yes |
+| `POST` | `/api/v1/messages` | Send a message to a Reddit user with automatic account selection | admin | yes |
 | `GET` | `/api/stats` | Get bot statistics | read | no |
 | `GET` | `/api/analytics/candidate-funnel` | Get durable candidate funnel counts | read | no |
 | `GET` | `/api/activity` | Get recent activity | read | no |