Add support for new musig2 signing scheme (sign branch only)

* client and application update

* fix: sweeper and tests

* improve common/musig2.go

* validation.go error message

* Update server/internal/core/application/covenantless.go

Co-authored-by: Pietralberto Mazza <[email protected]>
Signed-off-by: Louis Singer <[email protected]>

* Update common/bitcointree/builder.go

Co-authored-by: Pietralberto Mazza <[email protected]>
Signed-off-by: Louis Singer <[email protected]>

* add psbt_test.go & fix lifetime encoding

* fix application, APIs and clients with tree.Musig2 struct

* RoundSigningEvent: add cosigners public key list involved in the tree

* rework client vtxo tree signer session

* go work sync

* signingAll boolean in API

* fix matrix of bytes encoding

* fix e2e test

* rename congestion_tree.go -> vtxo_tree.go

* Update common/bitcointree/builder.go

Co-authored-by: Pietralberto Mazza <[email protected]>
Signed-off-by: Louis Singer <[email protected]>

* Update common/bitcointree/builder.go

Co-authored-by: Pietralberto Mazza <[email protected]>
Signed-off-by: Louis Singer <[email protected]>

* fix musig2_test.go

* move musig2data setter to update

* fix e2e_test.go

* Improve readability of musig2 test (#8)

---------

Signed-off-by: Louis Singer <[email protected]>
Co-authored-by: Pietralberto Mazza <[email protected]>

Author: louisinger

api-spec/openapi/swagger/ark/v1/service.swagger.json

@@ -594,6 +594,20 @@
         }
       }
     },
+    "v1Musig2": {
+      "type": "object",
+      "properties": {
+        "cosignersPublicKeys": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "signingAll": {
+          "type": "boolean"
+        }
+      }
+    },
     "v1Node": {
       "type": "object",
       "properties": {
@@ -685,9 +699,6 @@
             "$ref": "#/definitions/v1Input"
           }
         },
-        "ephemeralPubkey": {
-          "type": "string"
-        },
         "notes": {
           "type": "array",
           "items": {
@@ -717,6 +728,9 @@
             "$ref": "#/definitions/v1Output"
           },
           "description": "List of receivers for to convert to leaves in the next VTXO tree."
+        },
+        "musig2": {
+          "$ref": "#/definitions/v1Musig2"
         }
       }
     },

api-spec/protobuf/ark/v1/service.proto

@@ -120,17 +120,22 @@ message GetBoardingAddressResponse {
 
 message RegisterInputsForNextRoundRequest {
   repeated Input inputs = 1;
-  optional string ephemeral_pubkey = 2;
-  repeated string notes = 3;
+  repeated string notes = 2;
 }
 message RegisterInputsForNextRoundResponse {
   string request_id = 1;
 }
 
+message Musig2 {
+  repeated string cosigners_public_keys = 1;
+  bool signing_all = 2;
+}
+
 message RegisterOutputsForNextRoundRequest {
   string request_id = 1;
   // List of receivers for to convert to leaves in the next VTXO tree. 
   repeated Output outputs = 2;
+  optional Musig2 musig2 = 3;
 }
 message RegisterOutputsForNextRoundResponse {}