feat: use IOTA Sponsoring Service to fund did:iota transactions

Cargo.toml

@@ -62,7 +62,10 @@ lazy_static = "1.4"
 mime = { version = "0.3" }
 oauth_tsl = { git = "https://github.com/impierce/oauth-token-status-list", rev = "0aa0228" }
 once_cell = { version = "1.19" }
-product_common = { git = "https://github.com/iotaledger/product-core", tag = "v0.8.2", package = "product_common" }
+product_common = { git = "https://github.com/iotaledger/product-core", tag = "v0.8.2", package = "product_common", features = [
+    "gas-station",
+    "default-http-client",
+] }
 rand = "0.9"
 reqwest = { version = "0.12", default-features = false, features = [
     "json",

agent_api_http/postman/ssi-agent.postman_collection.json

@@ -2281,6 +2281,29 @@
 					"response": []
 				}
 			]
+		},
+		{
+			"name": "public",
+			"item": [
+				{
+					"name": "Show sponsoring configuration",
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{HOST}}/public/sponsoring-configuration",
+							"host": [
+								"{{HOST}}"
+							],
+							"path": [
+								"public",
+								"sponsoring-configuration"
+							]
+						}
+					},
+					"response": []
+				}
+			]
 		}
 	],
 	"auth": {

agent_api_http/src/lib.rs

@@ -1,3 +1,4 @@
+pub mod public;
 pub mod v0;
 
 pub mod error;
@@ -66,6 +67,7 @@ pub fn app(
         .merge(issuance_state.map(v0::issuance::router).unwrap_or_default())
         .merge(holder_state.map(v0::holder::router).unwrap_or_default())
         .merge(verification_state.map(v0::verification::router).unwrap_or_default())
+        .merge(public::router())
         // Trace layers
         .layer(
             ServiceBuilder::new()

agent_api_http/src/public/mod.rs

@@ -0,0 +1,13 @@
+use axum::{routing::get, Router};
+
+pub mod sponsoring_configuration;
+
+pub fn router() -> Router {
+    Router::new().nest(
+        "/public",
+        Router::new().route(
+            "/sponsoring-configuration",
+            get(sponsoring_configuration::sponsoring_configuration),
+        ),
+    )
+}