Only support primary domain for Lightning Address

Part of the process of removing support for serving multiple domains
from a single akkounts instance.

Also puts the Lightning Address discovery routes under the .well-known
path. Combined, these changes simplify reverse-proxying to the
.well-known endpoints.

spec/requests/lnurlpay_spec.rb

@@ -2,59 +2,59 @@ require 'rails_helper'
 
 RSpec.describe "/lnurlpay", type: :request do
 
-  context "Non-existent user/address" do
-    describe "GET /lnurlpay/:address" do
+  context "Non-existent user" do
+    describe "GET /.well-known/lnurlpay/:username" do
       it "returns a 404" do
-        get lightning_address_path(address: "csw@kosmos.org")
+        get lightning_address_path(username: "csw")
         expect(response).to have_http_status(:not_found)
       end
     end
 
-    describe "GET /lnurlpay/:address/invoice" do
+    describe "GET /lnurlpay/:username/invoice" do
       it "returns a 404" do
-        get lnurlpay_invoice_path(address: "csw@kosmos.org", params: { amount: 5000 })
+        get lnurlpay_invoice_path(username: "csw", params: { amount: 5000 })
         expect(response).to have_http_status(:not_found)
       end
     end
 
-    describe "GET /keysend/:address/" do
+    describe "GET /.well-known/keysend/:username/" do
       it "returns a 404" do
-        get lightning_address_keysend_path(address: "csw@kosmos.org")
+        get lightning_address_keysend_path(username: "csw")
         expect(response).to have_http_status(:not_found)
       end
     end
   end
 
-  context "Valid user/address" do
+  context "Valid user" do
     let(:user) { create :user, cn: 'satoshi', ou: 'kosmos.org', ln_account: 'abcdefg123456' }
 
     before do
       login_as user, :scope => :user
     end
 
-    describe "GET /lnurlpay/:address" do
+    describe "GET /.well-known/lnurlpay/:username" do
       it "returns a formatted Lightning Address response" do
-        get lightning_address_path(address: "satoshi@kosmos.org")
+        get lightning_address_path(username: "satoshi")
 
         expect(response).to have_http_status(:ok)
 
         res = JSON.parse(response.body)
         expect(res["status"]).to eq('OK')
         expect(res["tag"]).to eq('payRequest')
-        expect(res["callback"]).to match(lnurlpay_invoice_path('satoshi@kosmos.org'))
+        expect(res["callback"]).to match(lnurlpay_invoice_path('satoshi'))
         expect(res["minSendable"]).to be_a(Integer)
         expect(res["maxSendable"]).to be_a(Integer)
         expect(res["commentAllowed"]).to be_a(Integer)
       end
     end
 
-    describe "GET /lnurlpay/:address/invoice" do
+    describe "GET /lnurlpay/:username/invoice" do
       before do
         allow_any_instance_of(User).to receive(:ln_create_invoice).and_return("lnbc50u1p3lwgknpp52g78gqya5euvzjc53fc6hkmlm2rfjhcd305tcmc0g9gaestav48sdq4gdhkven9v5sx6mmwv4ujzcqzpgxqyz5vqsp5skkz4jlqr6tkvv2g9739ygrjupc4rkqd94mc7dfpj3pgx3f6w7qs9qyyssq7mf3fzcuxlmkr9nqatcch3u8uf4gjyawe052tejz8e9fqxu4pncqk3qklt8g6ylpshg09xyjquyrgtc72vcw5cp0dzcf406apyua7dgpnfn7an")
       end
 
       it "returns a formatted lnurlpay response" do
-        get lnurlpay_invoice_path(address: "satoshi@kosmos.org", params: {
+        get lnurlpay_invoice_path(username: "satoshi", params: {
           amount: 50000, comment: "Coffee time!"
         })
 
@@ -69,7 +69,7 @@ RSpec.describe "/lnurlpay", type: :request do
 
       context "amount too low" do
         it "returns an error" do
-          get lnurlpay_invoice_path(address: "satoshi@kosmos.org", params: {
+          get lnurlpay_invoice_path(username: "satoshi", params: {
             amount: 5000, comment: "Coffee time!"
           })
           expect(response).to have_http_status(:ok)
@@ -81,7 +81,7 @@ RSpec.describe "/lnurlpay", type: :request do
 
       context "comment too long" do
         it "returns an error" do
-          get lnurlpay_invoice_path(address: "satoshi@kosmos.org", params: {
+          get lnurlpay_invoice_path(username: "satoshi", params: {
             amount: 5000000, comment: "Coffee time is the best time, so here's some money for you to get some. May I suggest to sample some Pacamara beans from El Salvador?"
           })
           expect(response).to have_http_status(:ok)
@@ -92,9 +92,9 @@ RSpec.describe "/lnurlpay", type: :request do
       end
     end
 
-    describe "GET /keysend/:address/" do
+    describe "GET /.well-known/keysend/:username/" do
       it "returns a formatted Lightning Address keysend response" do
-        get lightning_address_keysend_path(address: "satoshi@kosmos.org")
+        get lightning_address_keysend_path(username: "satoshi")
 
         expect(response).to have_http_status(:ok)