invoices: self-contained payout addresses

Crypto options were limited to a hard-coded asset list, with one
address per coin in a side table. A payout address now carries
everything an invoice needs: ticker, name, QR URI scheme, amount
parameter, CoinGecko id, address and an active flag. Any coin can be
added, several addresses per ticker are fine, and known tickers fill the
QR and rate fields from the built-in templates.

The new-invoice form picks a payout address. The invoice snapshots the
ticker, address, name, scheme and amount parameter, and the PDF and QR
render from that copy, so editing, retiring or deleting a payout entry
never changes an issued invoice. "Fetch live" looks up the rate by the
payout address's CoinGecko id.

Migration 012 keeps the existing rows and backfills both the payout
metadata and the snapshots on existing crypto invoices.

Assisted-by: Claude:opus-5

test/invoice_test.rb

@@ -71,14 +71,32 @@ class InvoiceTest < Minitest::Test
     assert_equal BigDecimal('1.25'), inv.crypto_amount_due
   end
 
-  def test_build_rejects_unknown_coin
+  def test_build_fills_known_ticker_from_template
+    inv = Invoice.build(
+      client_name: 'ACME', client_email: 'billing@example.com', currency: 'EUR', gel_rate: '3.05',
+      items: [{ 'description' => 'work', 'qty' => '1', 'unit_price' => '100' }],
+      crypto_coin: 'ltc', crypto_address: 'ltc1qexampleexampleexampleexample'
+    )
+    assert_equal ['Litecoin', 'litecoin', 'amount'], [inv.crypto_name, inv.crypto_scheme, inv.crypto_amount_param]
+  end
+
+  # Any ticker works once a payout address defines it; the invoice keeps
+  # its own copy of the QR metadata.
+  def test_build_takes_snapshot_for_custom_coin
+    inv = Invoice.build(
+      client_name: 'ACME', client_email: 'billing@example.com', currency: 'EUR', gel_rate: '3.05',
+      items: [{ 'description' => 'work', 'qty' => '1', 'unit_price' => '100' }],
+      crypto_coin: 'DOGE', crypto_address: 'D6examplexampleexampleexample',
+      crypto_name: 'Dogecoin', crypto_scheme: 'dogecoin', crypto_amount_param: 'amount'
+    )
+    assert_equal ['DOGE', 'Dogecoin', 'dogecoin'], [inv.crypto_coin, inv.crypto_name, inv.crypto_scheme]
+  end
+
+  def test_build_rejects_malformed_ticker
     assert_raises(ArgumentError) do
-      Invoice.build(
-        client_name: 'ACME', client_email: 'billing@example.com',
-        currency: 'EUR', gel_rate: '3.05',
-        items: [{ 'description' => 'work', 'qty' => '1', 'unit_price' => '100' }],
-        crypto_coin: 'DOGE', crypto_address: 'D6examplexampleexampleexample'
-      )
+      Invoice.build(client_name: 'A', client_email: 'a@example.com', currency: 'EUR', gel_rate: '3',
+                    items: [{ 'description' => 'w', 'qty' => '1', 'unit_price' => '1' }],
+                    crypto_coin: 'bad coin', crypto_address: 'D6examplexampleexampleexample')
     end
   end
 end
@@ -86,7 +104,7 @@ end
 class InvoiceValidationTest < Minitest::Test
   BASE = {
     client_name: 'ACME', client_email: 'billing@example.com', currency: 'EUR',
-    gel_rate: '3.05', crypto_coin: 'LTC', crypto_address: '', crypto_rate: '', crypto_amount: '',
+    gel_rate: '3.05', payout_id: '', crypto_rate: '', crypto_amount: '',
     items: [{ 'description' => 'work', 'qty' => '1', 'unit_price' => '100' }]
   }.freeze
 
@@ -122,17 +140,21 @@ class InvoiceValidationTest < Minitest::Test
     assert_includes validate(items: [{ 'description' => '', 'qty' => '1', 'unit_price' => '1' }]), :items
   end
 
-  def test_crypto_address_format
-    assert_includes validate(crypto_address: 'not!an@address'), :crypto_address
+  def test_unknown_or_inactive_payout_rejected
+    assert_includes validate(payout_id: '999999'), :payout_id
+    p = PayoutAddress.create(coin: 'LTC', name: 'Litecoin', address: 'ltc1qvalidvalidvalidvalid', active: false,
+                             updated_by: 't', updated_at: Time.now.utc)
+    assert_includes validate(payout_id: p.id.to_s), :payout_id
+    p.update(active: true)
+    assert_empty validate(payout_id: p.id.to_s)
+  ensure
+    p&.destroy
   end
 
-  def test_crypto_unknown_coin_rejected
-    v = validate(crypto_coin: 'DOGE', crypto_address: 'D6exampleexampleexampleexample')
-    assert_includes v, :crypto_coin
-  end
-
-  def test_crypto_valid_asset_passes
-    v = validate(crypto_coin: 'USDT-TRC20', crypto_address: 'TXYZexampleexampleexampleexample12')
-    assert_empty v
+  def test_crypto_rate_must_be_positive
+    p = PayoutAddress.create(coin: 'LTC', name: 'Litecoin', address: 'ltc1qvalidvalidvalidvalid', updated_by: 't', updated_at: Time.now.utc)
+    assert_includes validate(payout_id: p.id.to_s, crypto_rate: '-1'), :crypto_rate
+  ensure
+    p&.destroy
   end
 end