v2.1.0: vc-vault-factory v0.4.0 compatibility

Makes the dApp fully compatible with the v0.4.0 API (vc-vault-factory + single-tenant vaults, on-chain fees, open issuance). The dApp talks to the ACTA REST API directly, so this tracks the new endpoint shapes and the inverted (deny-by-exception) issuer model.

Fixed

• Credential revocation now sends owner so the API can derive the single-tenant vault (revoke previously failed).
• Vault existence detection no longer simulates the removed authorize_issuer(owner, owner) against the (now factory) contract id. It uses GET /contracts/vault/:owner and treats version != null as "vault deployed". Fixes the dashboard "create vault" state and the Impacta sponsored flow.
• Credential detail field labelled "WALLET" showed the opaque did:stellar id. The holder is a DID, not a wallet, so it is now labelled "DID" and shows the full did:stellar:....

Changed

• Issuance is open by default (deny-by-exception): removed the pre-issue self-authorize step.
• "Authorize" page is now "Issuer access": a block-list manager (block via deny-issuer, unblock via allow-issuer), reading the blocked list from GET /contracts/vault/issuers/denied.
• useVault: authorizeSelf / checkSelfAuthorized removed; authorizeAddress / revokeAddress replaced by allowIssuer / denyIssuer.
• /config tolerates the new fields (factoryContractId, etc.); actaContractId still read as a back-compat alias.
• i18n updated (en / es / fr) for the issuer-access / block-list copy.

Dependencies

• Bumped next 16.2.3 -> 16.2.6, form-data 4.0.5 -> 4.0.6, js-yaml 4.1.1 -> 4.3.0, @protobufjs/utf8 1.1.0 -> 1.1.1.

Docs

• Rewrote README.md for the v0.4.0 model (single-tenant vaults via the factory, did:stellar issuer, issuer-access block-list, direct REST API client, network/env config).

Notes

• Issuing requires a registered, resolvable did:stellar (Dashboard -> My DID); the API enforces the controller<->DID binding.
• Requires the ACTA API v1.1.1 (vc-vault-factory v0.4.0).