File a support issue from the customer portal

Creates an incident in the internal ops queue tagged with `customer-reported` plus the caller's orgId. Body fields: `title` (5–200 chars), `description` (20–5000 chars), `severity` (`low` / `medium` / `high`, defaults to `medium`). Capped at 5 calls per org per rolling 24h window — over-cap requests return 429 with `Retry-After`. The response carries the new incident id so the customer can reference it with support.