`GET /billing/plans` — the public plan catalog. **Unauthenticated** (the signup page reads it before an org exists) and stateless: composed from the compiled-in `plan-defaults` / `pricing-defaults` codegen + the hand-written plan-catalog labels/features. The single wire source that replaces the frontend's `PRICING_PLANS` constant.

{  "currency": "string",  "plans": [    {      "annual_cents": 0,      "description": "string",      "features": {        "dedicated_support": true,        "sla_guarantees": true      },      "limits": {        "gb_exported": 0,        "gb_ingested": 0,        "gb_scanned": 0,        "gb_stored": 0      },      "monthly_cents": 0,      "name": "string",      "target_audience": "string",      "tier": "startup"    }  ]}