fix: aqua_sign workflow picks up personal identity instead of server identity

The server identity lookup in the aqua_sign workflow (explorer.ts) only
checked for forms_type "simple_claim", matching any user's identity claim
on the server wallet. Now also requires forms_claim_context
"Self issued server identity", consistent with the fix in server_attest.ts.

Closes #754

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Arthur-Kamau

api/src/controllers/explorer.ts

@@ -403,7 +403,7 @@ export default async function explorerController(fastify: FastifyInstance) {
                         const entryGenHash = getGenesisHash(entryAquaTree)
                         if (entryGenHash) {
                             const genRevision = entryAquaTree.revisions[entryGenHash]
-                            if (genRevision && genRevision["forms_type"] === "simple_claim") {
+                            if (genRevision && genRevision["forms_type"] === "simple_claim" && genRevision["forms_claim_context"] === "Self issued server identity") {
                                 serverIdentityAquaTree = entryAquaTree
                                 serverIdentityFileObjects = entryFileObjects
                                 break