wb-147: Add ecosystem overview diagram to architecture overview

blueprint/03-architecture-overview.md

@@ -10,11 +10,20 @@ While the previous chapter describes the regulatory and architectural frameworks
 
 ## The Ecosystem at a Glance
 The EUDI Wallet and EBW ecosystem follows the common three-party attestation model. In this model, three primary actors interact: issuer, holder and verifier. A trust framework supports these actors by providing the trust anchors used for validation.
-1. **Holder** – the wallet controlled by a natural or legal person.
+1. **Holder** – the wallet controlled by a natural person or economic operator.
 2. **Issuer** – an entity that issues attestations to the Holder.
 3. **Verifier** – a relying party that receives and validates attestations presented by the Holder.
 4. **Trust framework** – the infrastructure used to validate trust relationships between ecosystem participants (described in Chapter 6).
 
+The diagram below shows the **WE BUILD reference pattern** for the ecosystem.
+
+![Ecosystem overview](../images/ecosystem-overview.png)
+*Figure 1: WE BUILD reference pattern for the EUDIW / EBW ecosystem.*
+
+In this reference pattern, Issuers use the issuance capabilities of the European Business Wallet (EBW) to issue attestations to the Holder; the Holder uses the EUDI Wallet (for natural persons) or the European Business Wallet (for economic operators) to present attestations to the Verifier; and Verifiers use the verification capabilities of the European Business Wallet to validate the attestations presented by the Holder. The foundation of the ecosystem is the Trust framework, where Issuers publish keys, identifiers and schemas, and Verifiers register as Relying Parties.
+
+The EBW is an architectural construct (a defined role and set of capabilities), not a regulated entity, certification artefact, or deployment specification. The reference pattern is what the WE BUILD pilots are designed to evidence; it does not preclude conformant implementations that follow a different architectural choice. Regulatory paths follow the attestation tier: QEAAs are issued via the QEAASP path under eIDAS2 with the EBW operating outside that certified scope, while PuB-EAAs (including the EBWOID) are anchored in the relevant authentic source.
+
 ## System Landscape
 The diagram below illustrates the baseline trust topology of the EU wallet ecosystem. Issuers provide attestations to holders, holders present them to verifiers, and all actors validate trust relationships using the trusted lists.
 The trusted lists specify the recognised participants in schemes for electronic identification and trust services.